Cloudless Sulphur: All You Need to Know for Butterfly Enthusiasts

The Cloudless Sulphur is a stunning yellow butterfly that can easily brighten up any garden or outdoor space. Found throughout most of the mainland United States, it’s most common in the eastern US and southern portions of the western US, sometimes reaching Canada 1. The scientific name for this beautiful creature is Phoebis sennae, which draws inspiration from Phoebe, sister of the sun godApollo in Greek and Roman mythology, and the genus Senna – home to many of the butterfly’s host plants for larvae 2.

These captivating insects go through a fascinating life cycle, starting as eggs and transforming into caterpillars, then pupae, and finally emerging as adult butterflies. Observing Cloudless Sulphurs in your garden can bring a deeper appreciation for the extraordinary natural world. Male Cloudless Sulphurs boast lemon-yellow wings with no markings, while females can exhibit either yellow or white wings with irregular, patchy black borders and dark spots 3.

Cloudless Sulphur: Overview

Physical Characteristics

The Cloudless Sulphur, also known as Phoebis sennae, is a large, vibrant butterfly species. Their wingspan ranges from 2 to 2¾ inches (5.4 – 7.0 cm). There are some distinguishing features between males and females:

  • Males: lemon yellow upper surface, no markings
  • Females: yellow or white upper surface, irregular patchy black borders, dark spot on upper forewing

The lower surface of the hindwing in both sexes showcases two pink-edged silver spots.

Distribution and Habitat

These butterflies are mostly found in the eastern United States and southern areas of the western United States, with some sightings reported in Canada. In Florida, they are considered one of the most common butterfly species.

The Cloudless Sulphur’s preferred habitat includes:

  • Gardens
  • Open fields
  • Road edges
  • Wetlands
  • Disturbed areas with host plants

They thrive in these environments by feeding on nectar from various flowers, often found in abundance in their habitat. Their larvae feed on host plants in the genus Senna, for which the species is scientifically named.

Feature Cloudless Sulphur
Scientific Name Phoebis sennae
Habitat Gardens, open fields, road edges, wetlands, and disturbed areas
Larval Host Plants Senna species
Average Wingspan 2 to 2¾ inches (5.4 – 7.0 cm)
Distinguishing Features Yellow or white upper surface with black borders and silver spots on the hindwings

Life Cycle and Behavior

Caterpillar Stage

The caterpillar of the cloudless sulphur goes through several stages of growth called instars. During this stage, they feed on host plant leaves1. Their primary food sources include various species of cassia plants, such as partridge pea2. Some notable characteristics of cloudless sulphur caterpillars include:

  • Green or yellow coloration
  • White or faint yellow lateral stripe
  • Interior feeders, living within rolled leaves for protection

Adult Butterfly Stage

The adult cloudless sulphur is an easily recognizable butterfly with its large, clear-yellow coloration. Males are typically solid yellow, while females have a yellow base with a black border on their wings, along with a dark spot at the center of each forewing3. A few key features of adult cloudless sulphurs include:

  • Long proboscis, allowing them to access nectar from long-tubed plants4
  • Rapid flight, especially during migration
  • Active during spring and summer months

The cloudless sulphur has a unique behavior of migrating southward in late summer and fall, which is easily observed in their rapid flight patterns5. As adults, they do not hibernate or undergo diapause6. Their long proboscis enables them to feed on nectar from the same long-tubed plants that serve as a food source for hummingbirds7.

Cloudless Sulphur Caterpillar Adult Cloudless Sulphur
Feeds on host plant leaves Feeds on nectar
Lives within rolled leaves Active during migration
Green or yellow color Clear-yellow color

Feeding and Nutrition

Nectar Plants

Cloudless Sulphur butterflies primarily feed on nectar from various plants. They have a preference for:

  • Cardinal flower: A bright-red flower attracting pollinators with its vibrant color.
  • Scarlet sage: A red tubular flower that attracts hummingbirds and butterflies alike.

Host Plants

The caterpillars of the Cloudless Sulphur have specific host plants, mainly in the Senna and Cassia families:

  • Senna: A group of plants with yellow flowers that provide essential nutrients for the larvae.
  • Cassia: A similar group of plants that also serves as a primary food source for the growing caterpillars.
Nectar Plants Host Plants
Cardinal flower Senna
Scarlet sage Cassia

Migration Patterns and Seasonality

The Cloudless Sulphur Butterfly is a large yellow butterfly that can be found across the mainland United States. Let’s explore its migration patterns and seasonality.

These pretty butterflies are known to migrate when the seasons change. They’re most commonly found in the eastern United States and southern portions of the western United States.

They’ve also been spotted as far north as Canada. The migration is driven by temperature changes, especially in the warmer months.

Some key features of the Cloudless Sulphur Butterfly are:

  • Large yellow color
  • Wingspan of 2 to 2¾ inches (5.4 – 7.0 cm)
  • Males have a lemon-yellow upper surface with no markings
  • Females may be yellow or white with irregular black borders
  • Lower surface of hindwing has 2 pink-edged silver spots

In general, the Cloudless Sulphur Butterfly has fascinating migration and seasonality patterns that vary depending on the region and climate.

Species Relationship and Interactions

The Cloudless Sulphur butterfly is a large yellow butterfly found throughout most of the mainland United States. It plays a significant role in pollination and has specific interactions with certain plants and animals.

One of the primary interactions involves the butterfly’s relationship with its host plants. Caterpillars feed on the leaves of plants from the pea family, such as Cassia and Senna species. Adult butterflies are attracted to bright-colored flowers where they can retrieve nectar. This process aids in pollination as they visit several flowers and facilitate the transfer of pollen.

Cloudless Sulphur butterflies also experience various predator-prey relationships. For example, they become prey for birds, spiders, and other insects. Additionally, they have developed defenses to avoid predation, such as camouflage, warning coloration, and swift flight patterns.

  • Host plants: Cassia and Senna species
  • Common predators: Birds, spiders, insects
  • Defenses: Camouflage, warning coloration, swift flight

In comparison to other butterfly species, the Cloudless Sulphur stands out due to its striking color and relatively larger size. While many butterfly species contribute to pollination, each has unique host plants and methods of survival. Butterflies interact with various species in their ecosystem, and recognizing their ecological significance allows us to understand the importance of preserving these delicate insects.

Feature Cloudless Sulphur Other Butterfly Species
Size Larger, wingspan up to 2.75 in Varies, generally smaller
Color Striking bright yellow Varies widely
Host Plants Cassia and Senna species Unique for each species
Role in ecosystem Pollination, predator-prey interactions Pollination, predator-prey interactions

Footnotes

  1. https://fieldguide.mt.gov/speciesDetail.aspx?elcode=IILEPB1010

  2. https://entnemdept.ufl.edu/creatures/bfly/bfly2/cloudless_sulphur.htm

  3. https://www.fs.usda.gov/wildflowers/pollinators/pollinator-of-the-month/cloudless-sulphur-butterfly.shtml

  4. https://alabama.butterflyatlas.usf.edu/species/details/113/cloudless-sulphur

  5. https://mdc.mo.gov/discover-nature/field-guide/cloudless-sulphur

  6. https://fieldguide.mt.gov/speciesDetail.aspx?elcode=IILEPB1010

  7. https://alabama.butterflyatlas.usf.edu/species/details/113/cloudless-sulphur

Reader Emails

Over the years, our website, whatsthatbug.com has received hundreds of letters and some interesting images asking us about these insects. Scroll down to have a look at some of them.

Letter 1 – Cloudless Sulfur Caterpillar, we believe

 

Caterpillar ID
Location: Tampa, FL
November 4, 2011 3:34 pm
We are located in Tampa, FL. My neighbor found a tree full of these yellow w/ black stripes caterpillars.
Any ideas? What will they turn into?
Signature: Thanks, Heidi

Cloudless Sulfur Caterpillar, possibly

Hi Heidi,
We believe we have correctly identified your caterpillar as that of a Cloudless Sulfur butterfly,
Phoebis sennae, though the resolution on your photo prohibits definitive identification.  If you can provide the name of the tree or a description of the tree, it might help to confirm our identification.  The caterpillars of the Cloudless Sulfur feed on the leaves and blossoms of Cassia and related trees.  These trees generally have showy yellow flowers.  Here is a photo on Bugguide of a Cloudless Sulfur caterpillar on the food plant.

Letter 2 – Sulphur Caterpillar: Orange Barred Sulphur???

 

Lime Green Caterpillars munching on Cassia Tree
Thu, May 7, 2009 at 11:48 AM
I have been trying to identify the lime green caterpillars currently munching on my recently transplanted Cassia Excelsa Tree. I saw the pictures on your site referring to the Cloudless Sulpher caterpillar and how it can be yellow or green depending on it eating the leaves or the flowers of the Cassia but I don’t think they are Cloudless Sulphers.The body structure of the caterpillar pictures I am sending is similar to the Cloudless but the striping on the side is much different. The Cloudless Sulpher appears to have more of a black banding around it. The caterpillars I have look to have a black short stripe sandwiching four longer stripes and then another short stripe. Also the head of the caterpillar is the entirely lime green with no black at all.Thank you for help.
JRS
Tampa Bay Area – Florida

Orange Barred Sulphur Caterpillar
Orange Barred Sulphur Caterpillar

Dear JRS,
Your caterpillar is definitely a Sulphur in the genus Phoebis.  We believe it to be a close relative of the Cloudless Sulphur, the Orange Barred Sulphur, Phoebis philea.  There is a photo posted to BugGuide that looks very similar to your specimen.

Orange Barred Sulphur Caterpillar
Orange Barred Sulphur Caterpillar

Letter 3 – Cloudless Sulphur Caterpillar

 

pretty yellow caterpillars devouring my shrub
We’ve got lots of these guys all over a yellow flowering tree/shrub in our yard (not esperanza). We’ve never seen them before because this is the first year the tree/shrub is flowering. It had been in a dry, shady spot prior but this spring we moved it to a sunny area where it benefits from our sprinkler system and so now is flowering like crazy. And these guys have moved in and are busily munching away. What are they?
Northwest Austin Thank you!
Vicki

Cloudless Sulphur Caterpillar
Cloudless Sulphur Caterpillar

Hi Vicki,
Losing a few blossoms is a small price to pay for the reward of the numerous clear yellow, fast flying Cloudless Sulphur Butterflies, Phoebis sennae, that will fly about your garden after the metamorphosis is complete. Interestingly, Cloudless Sulphur caterpillars that feed on the leaves of Cassia are green, and those that feed on the flowers are yellow.

Letter 4 – Cloudless Sulphur Caterpillar from Brazil

 

Phoebis sennae marcellina
Location: Londrina-Paraná-BRASIL
April 9, 2012 2:54 pm
Phoebis sennae marcellina
Signature: Eduardo Lucof

Cloudless Sulphur Caterpillar

Hi again Eduardo,
Thank you for submitting your four caterpillar photos from Brazil.  We are posting the Cloudless Sulphur Caterpillar,
Phoebis sennae marcellina, and we will try to post others if time permits.  Cloudless Sulphurs are now residents in the Los Angeles area where the What’s That Bug? offices are located.  They are not native, but cultivation of their food plants, the cassia tree, in gardens has provided a source of food for the caterpillars enabling the species to establish itself.  We are linking to the Butterflies of America page on the Cloudless Sulphur.

Letter 5 – Clouded Skipper Caterpillar, we believe

 

Subject:  Caterpillar
Geographic location of the bug:  Cary NC
Date: 06/15/2021
Time: 03:56 PM EDT
Your letter to the bugman:  Found this little guy nibbling on my corn leaves. Would love to know what it is.
How you want your letter signed:  Winters

Probably Clouded Skipper Caterpillar

Dear Winters,
We believe based on this BugGuide image that you have a Clouded Skipper Caterpillar,
Lerema accius.  According to BugGuide:  “Caterpillars host on grasses” and since Corn is a grass, it is a possible food plant.  According to the Alabama Butterfly Atlas:  “The caterpillar is greenish-white with a mid-dorsal dark stripe and two white lateral stripes. The head is white with a black margin and three vertical black stripes on the facial region. The body is covered with numerous minute white dots.”

Probably Clouded Skipper Caterpillar

Letter 6 – Cloudless Sulphur

 

What type of sulphur butterfly is this?
Fri, Jan 16, 2009 at 11:29 AM
I took a picture of this butterfly while in South Florida on the edge of the Loxahatchee River. I would say the plants in the area are typical of south florida and or wetlands. I found various sulphur butterflies, but I could not find any that were the same green color and am hoping you could help me to identify it.
Madcalabrian
Riverbend Park, Jupiter Florida

Cloudless Sulphur
Cloudless Sulphur

Dear Madcalabrian,
This sure looks like a Cloudless Sulphur, Phoebis sennae, to us.  According to BugGuide, the Cloudless Sulphur may be identifiede by the following description:  “upperside of male wings lemon yellow or pale greenish-yellow with no markings; female forewing with small dark spot, usually a narrow blackish outer margin, and a few vague dark dots near tip. Underside of hindwing with two silver black-rimmed spots in both sexes.”  This butterfly breeds in the Southern states and strays north in the fall.

Letter 7 – Cloudless Sulphur

 

Subject: Yellow Butterfly
Location: West Los Angeles
October 9, 2016 4:11 pm
These have been around the backyard for years but they don’t usually sit still long enough to grab the camera to take a picture. This picture was taken 10-9-16 in in West Los Angeles area. The flower is a Cape Marigold and this particular butterfly seems attracted to only the yellow flowers of that plant.
Signature: Phil Hackett

Cloudless Sulphur
Cloudless Sulphur

Hi Phil,
This is one of the Sulphur butterflies in the genus
Phoebis, and we are pretty certain it is the Cloudless Sulphur, Phoebis sennae.  This is a very fast flying species, and it is our experience that they are difficult to approach, so your images are a marvelous addition to our site.  According to BugGuide:  “upperside of male wings lemon yellow or pale greenish-yellow with no markings; female forewing with small dark spot, usually a narrow blackish outer margin, and a few vague dark dots near tip. Underside of hindwing with two silver black-rimmed spots in both sexes.”

Cloudless Sulphur
Cloudless Sulphur

Letter 8 – Cloudless Sulphur Puddling in the heat

 

Subject: Cloudless Sulphur puddling
Geographic location of the bug:  Mount Washington, Los Angeles, California
Date: 07/06/2018
Time: 05:15 PM EDT
Last week when temperatures in Los Angeles reached triple digits, Daniel was watering and he was lucky enough to be able to approach a normally very wary and fast flying Cloudless Sulphur as it puddled at the mud created by the hose.

Cloudless Sulphur

 

Letter 9 – Cloudless Sulphur Caterpillar

 

what is this caterpillar?
Hi Bugman,
I found this caterpillar in Santa Barbara, California. I found it interesting that it matched the color of the plant I found it on. I have looked around a bit on the web to identify it without any luck. Can you help? Also, any idea which plant it is eating? Thank you!!
Dan Sullivan

Hi Dan,
This is a Cloudless Sulphur Caterpillar, Phoebis sennae, also called the Senna Sulphur. The butterfly is a large, clear yellow, fast flying species. The plant is Senna. As a means of camouflage, the caterpillars are often green when feeding on the leaves, and yellow when feeding on the blossoms.

Letter 10 – Cloudless Sulphur Caterpillar

 

Subject: Yellow caterpillar Tucson AZ
Location: Oro Valley, AZ on Narana Road
October 9, 2015 11:50 am
What does this caterpillar become?
Signature: Curious

Cloudless Sulphur Caterpillar
Cloudless Sulphur Caterpillar

Dear Curious,
This is the caterpillar of a Cloudless Sulphur butterfly,
Phoebis sennae, and the caterpillars have both green and yellow forms.  The adult Cloudless Sulphur is a beautiful yellow butterfly.  According to BugGuide:  “Caterpillar feeds most commonly on Cassia and some other woody and herbaceous legumes.”  Interestingly, the yellow caterpillars are quite well camouflaged when feeding on the yellow flowers of the plants and the green caterpillars are well camouflaged when feeding on the leaves.  It is our theory that the green caterpillars feeding on the flowers were eaten by birds and the yellow caterpillars feeding on leaves were eaten by birds, and not that the caterpillars are able to change color when feeding on either flowers or leaves.  We have a nice series of images of the metamorphosis of the Cloudless Sulphur in our archives.

Thank you
Liane Futch

Letter 11 – Cloudless Sulphur Caterpillar

 

Subject:  Cloudless Sulphur Caterpillar in Mount Washington
Location:  Mount Washington, Los Angeles, California
February 28, 2016
We were shocked to see this bright yellow caterpillar meandering across the patio.  We immediately recognized a Cloudless Sulphur Caterpillar,
Phoebis sennae, but we do not have any Cassia growing anywhere near.  Where did it come from?  We checked BugGuide and learned:  “Caterpillar: usually pale green and marked by a yellow stripe on each side and black spots in rows across each abdominal segment.  Above and below the yellow stripe there are usually small areas marked with blue.   There is also a yellow form that occurs when it feeds on yellow flowers of its host plants. The later instars of the yellow form have a dark transverse band across each segment” which means our Caterpillar was feeding on yellow blooms.  According to BugGuide:  “Caterpillar feeds most commonly on Cassia and some other woody and herbaceous legumes” and we do have an Acacia in the garden, another legume in the family Fabaceae , so we will check it out to see if there are any additional Cloudless Sulphur Caterpillars feeding upon it.

Cloudless Sulphur Caterpillar
Cloudless Sulphur Caterpillar
Cloudless Sulphur Caterpillar
Cloudless Sulphur Caterpillar

Letter 12 – Cloudless Sulphur Caterpillar

 

Subject: identification
Location: Tucson, AZ
October 6, 2016 6:04 pm
Dear Bugman,
I am submitting a few photos of insects for identification. They were taken between October 1 and 4 2016 in our community garden in Tucson, AZ.
Image 1 I believe to be a bee fly, perhaps of genus Exoprosopa.
Image 2. is a caterpillar (Sulphur of some sort?) on Lindheimers Senna
Image 3 fairly large sized ants
I would be very happy if you could identify the insets in these photos that I would like to share with my fellow gardeners.
Thanks very much!
Signature: Melody

Cloudless Sulphur Caterpillar
Cloudless Sulphur Caterpillar

Dear Melody,
Unless there is a good reason, like a predator/prey relationship, we tend to confine our postings to a single species, or closely related species for classification purposes on our site.  We will be dealing with your identification requests one at a time.  The caterpillar is that of a Cloudless Sulphur,
Phoebis sennae, which you can verify by comparing your image to this BugGuide image.  The caterpillars are found in both a yellow and green form, with the yellow caterpillars feeding on blossoms and the green ones feeding on leaves.

Letter 13 – Cloudless Sulphur Caterpillars (or possibly Orange-Barred Sulphur)

 

Caterpillars on Cassia
I found these two on my cassia last week. I think the one with stripes running the length is a sulphur of some kind. Any idea about the other one?
Donna Williams
DeLand, Florida

Hi Donna,
We are pretty certain both of your caterpillars are the same species, the Cloudless Sulphur, Phoebis sennae, a beautiful, swift flying, shrome yellow butterfly. BugGuide pictures two color forms of the caterpillar, green with longitudinal stripes, and yellow with traverse stripes. The yellow form is reportedly more common when the caterpillar feeds on flowers, but both of your specimens seems to be feeding on the flowers.

Sulphurs (11/16/2006)
Hey Guys, The pic on the right could also be Orange barred sulphur (Phoebis philea). I’ve seen then both feeding on species of Cassia and Senna in Southern Florida. Sometimes they feed on the same plant. We have them both here on the Gulf Coast of Texas, as well. I took a few of each and raised them, and when they’re in the Yellow/flower eating from they look alot alike. Just wanted to share. Eric Duran
Nature Discovery Center
Bellaire, TX

Letter 14 – Cloudless Sulphur Chrysalis

 

Can you ID me?
Hi Bugman,
Can you please help me identify this “thing”…. I live in Coconut Creek, Florida and saw this on one of my Jasmine plants that I recently brought home from the nursery (bonus!!). I’ve searched the internet far and wide but … just haven’t come across anything that looks like this. Can you help ID me? Thanks so much!
Debi
PS – LOVE your website.

Hi Debi,
This is the Chrysalis of a large yellow butterfly known as the Cloudless Sulphur, Phoebis sennae, sometimes called the Senna Sulphur, though it might also be from a close relative, the Orange Barred Sulphur, Phoebis philea.

Update on Comment: 
Dead Chrysalis
November 7, 2011 8:47 am
Of course I could be wrong, but after having raised thousands of sulphurs, the color isn’t right.  The dark spot where the pupa narrows is one sign.  The general color is another.  Normally they are one color pretty much all over.
http://www.butterflyfunfacts.com/images/cloudlesssulphur5colorpupae6.jpg Brown in these pupae is a bad sign.  Yellow wings show through, not beige or brown.  There can be a coral colored chrysalis but not this ‘dirty’ look.
http://www.butterflyfunfacts.com/images/cloudlesssulphurchrysalisorange6.jpg  I learn more everytime I visit your site.  Thank you!
Signature: Edith Smith

Letter 15 – Female Clouded Sulphur

 

What is this butterfly?
October 8, 2009
This butterfly has black edges and the rest is yellow other than one black spot on each upper wing and one yellow spot on each lower wing. I would really just like the scientific name.
scientific name?
Manchester, NH

Clouded Sulphur
Clouded Sulphur

Dear scientific name?
This is a Sulphur Butterfly in the genus Colias.  We believe it is a female Clouded Sulphur, Colias philodice.  It is the white form of the female, a common variation.  Both the Clouded Sulphur and the Orange Sulphur, Colias eurytheme, have a white form female.  According to BugGuide, the best way to distinguish the two from one another is:  “The white form female philodice can often be separated from the white form female eurytheme by the HW outer margin. In philodice the HW outer margin will have a more narrow smoother solid black border, while eurytheme most often has an irregular and wider black border, many times with diffuse white markings within the black border.
”  BugGuide also has photos that illustrate this difference.  Actually, upon closer inspection, we believe this to be the typical yellow form of the female Clouded Sulphur.  The female can be distinguished from the male in that the black borders on the wings of the female have spots, and the male has solid black borders.

Letter 16 – Male Cloudless Sulphur

 

Subject: Another Sulphur Butterfly 🙂
Location: Coryell County, Texas
October 10, 2016 8:32 pm
Another morning of gardening, another beautiful yellow butterfly visiting the Autumn Sage (Salvia greggii). I wish I could capture how beautiful these butterflies are! It’s tough for me to get the yellows and whites to show as more than bright blurs in the sunshine.
I think this is another Sulphur, but can’t tell which species.
Such gorgeous weather, 70’s to 80’s, no rain this week.
Thank you for all of your help throughout the months, seasons and years!
Signature: Ellen

Male Cloudless Sulphur
Male Cloudless Sulphur

Dear Ellen,
This individual is a male Cloudless Sulphur,
Phoebis sennae, which you can verify by comparing to this BugGuide image.  Interestingly, it appears to be nectaring from the same type of sage plant.  According to BugGuide:  “upperside of male wings lemon yellow or pale greenish-yellow with no markings; female forewing with small dark spot, usually a narrow blackish outer margin, and a few vague dark dots near tip. Underside of hindwing with two silver black-rimmed spots in both sexes.”  Your one image nicely illustrates the “male wings lemon yellow or pale greenish-yellow with no markings.”  We suspect the appearance of this male Cloudless Sulphur is a good indication that the image you submitted last week is a female Cloudless Sulphur.  Butterflies in motion can be difficult to capture in images, but we think you are doing a marvelous job and your images are a good indication of the patience you have with your uncooperative subjects.  

Male Cloudless Sulphur
Male Cloudless Sulphur

Letter 17 – Sulphur Butterfly

 

Butterfly
Location:  Columbia SC
October 2, 2010 12:57 pm
My cousin sent me this picture. It was recently taken (early fall). It is such a pretty color and I’d like to be able to identify it. Please help. Thank you
Signature:  Brenda

Sulphur Butterfly

Hi Brenda,
We are able to provide you with a genus, but an exact species may be difficult as all the Sulphurs in the genus
Colias look rather similar on the undersides.  You may scan the possibilities on BugGuide to see what we mean.  Your photo is somewhat disturbing.  Something just doesn’t seem right to us.  We can’t help but wonder if perhaps this lovely Sulphur has become a meal for an unseen predator, more specifically a Crab Spider or Flower Spider.  Crab Spiders wait on blossoms to ambush pollinating insects.  something about the way the bloom has engulfed the butterfly has lead us in that supposition.

Letter 18 – Sulphur Caterpillar

 

Probably so simple — what’s this caterpillar?
Hi, Bugman — it’s 2:08 a.m. and I’ve been looking through your website for a couple of hours. I really ought to be trying to get some sleep — I am a stay-at-home Dad of 19-month old twins — but the site is fascinating. When a question about a furry caterpillar’s identification came up at the playground today, I gave two people your web address. I have seen these caterpillars before but never photographed any until tonight. I didn’t see anything quite the same on your site, so I’d like your help. Any thoughts? My wife and I live in Arlington, Va, in case that’s helpful. Many thanks for a great site and lots of interesting photos and information.
Thanks again for hours of fun.
David Foose

Hi David,
If you only knew about the hours we spent on our site instead of sleeping. This appears to be a Sulphur Butterfly Caterpillar in the genus Colias. Caterpillars feed on clover, alfalfa and other legumes.

Letter 19 – Female Cloudless Sulphur, we believe

 

Subject: Yellow Butterfly, a Cloudless Sulphur, perhaps?
Location: Coryell County
October 8, 2016 7:04 pm
Hello again!
Many butterflies today. I think this may be a Cloudless Sulphur (Phoebis sennae), but I’m not sure. Thes are quite large, and only visit the salvia greggi (Autumn sage), ignoring the other flowers in the garden. I believe you identified a similar butterfly for me several years ago, thank you!
Best wishes for a great autumn!
Signature: ellen

Sulphur, but which species?
Probably Female Cloudless Sulphur

Dear Ellen,
You are correct that this is a Sulphur in the genus
Pheobis, but we cannot say for certain which species.  Your individual does resemble the Cloudless Sulphur in this BugGuide image, but it also resembles this Orange Barred Sulphur, also pictured on BugGuide.  Unfortunately, the open-winged image you provided is lacking in critical detail.

Update
Subject: Sulphur: Cloudless or Orange-Barred? Part II
Location: Coryell County, TX
October 10, 2016 9:17 pm
Hello again! Thank you for your quick response. I saw the entry of the Cloudless Sulphur from Los Angeles, so beautiful.
I found this article on Orange-Barred Sulphurs (found now in California) and thought it was so interesting: http://www.monarchprogram.org/new-butterfly-species-in-the-southwest-the-orange-barred-sulfur-phoebis-philea/
I looked back at my photos and realized that, although too blurry, these show the sunlit color of the butterfly in question. It was lemon yellow, no orange that I ever spotted; I don’t know if that makes a difference or not. Gorgeous butterfly on the wing. Will keep trying to get clearer photos of the insects in our gardens.
Love your site! Thank you so much for all of the information.
Signature: Ellen

Cloudless Sulphur
Cloudless Sulphur

Hi again Ellen,
Thanks for the update.  We believe based on the images you just submitted of a male Cloudless Sulphur, that this is a female of the species.

Letter 20 – What’s Buzzing The Baccharis in Elyria Canyon Park??? Achmon Blue and others

 

The Baccharis that is blooming in Elyria Canyon Park is attracting a myriad of insects in search of nectar.
Location:  Elyria Canyon Park, Mount Washington, Los Angeles, CA
September 30, 2012

Baccharis near Red Barn in Elyria Canyon Park

The hedge of native Baccharis near the Red Barn in Elyria Canyon Park is about ten feet tall and it is currently in bloom.  There is a noticeable buzzing one hears upon approach, and that is caused by thousands of Honey Bees eagerly gathering nectar.  It seems Baccharis is a magnet for pollinating insects of all types, and without a doubt, the Honey Bees are the most numerous, but other insects can be spotted taking advantage of the bounty.

Honey Bees on Baccharis

Clare and Daniel made a trip on Saturday and though there was work to be done, Daniel used Clare’s camera to get a few photos.  The largest butterfly spotted on the Baccharis was a Painted Lady, Vanessa cardui, butDaniel was unable to get a photo with a spread wing view.

Painted Lady on Baccharis

Though the photo is quite out of focus, Daniel also managed to get a photo of this Checkered Skipper in the genus Pyrgus that did not want to hold still long enough to be photographed.

Checkered Skipper on Baccharis

A tiny creamy yellow butterfly was observed flying close to the ground, but it never landed, so no conclusive identification could be made.  Daniel returned today with a better camera and decided to document the visitors to the Baccharis.  A 50mm lens with a macro feature allowed for closeup photographs, however, since there was no zoom, the photographer often startled the insect subjects into flying away.  Luckily the tiny yellow butterfly made a return appearance and posed for two quick photos.  These photos substantiated a sighting local lepidopterist Julian Donahue made on August 23 of a Dainty Sulphur, Nathalis iole, though it is doubtful the individual Julian spotted over a month ago at his home is the same individual photographed in Elyria Canyon Park, which would indicate there may be a local population with noticeable numbers present in Mount Washington this summer.

Dainty Sulphur on Baccharis

There were at least three species of Gossamer Winged Butterflies present today, and the largest were the Gray Hairstreaks, Strymon melinus.  These little beauties have the habit of rubbing their hind wings together, perhaps to attract the attention of any predator into mistaking the tail and wing spots for the head of the butterfly and deflecting an attack from the vital organs to the expendable wings.

Gray Hairstreak and Honey Bee on Baccharis

Smaller than the Gray Hairstreak is another Gossamer Wing, the Marine Blue, Leptotes marina.  They were present in sufficient numbers to flutter about in small groups.

Marine Blue on Baccharis

The smallest of the Gossamer Winged Butterflies were another species of Blue, possibly the Achmon Blue, Plebejus acmon, though we are still awaiting Julian’s input on that identification.

Confirmation from Julian Donahue
NEW to the Mt. Washington Butterfly List! Good job, Daniel.
Although this is a tough group of butterflies to identify, it appears to be an Acmon Blue (Icaricia acmon). Larvae feed on Deerweed (Lotus scoparius, now Acmispon glaber) and Astragalus (none of this in Elyria that I know of); also on California Buckwheat, Eriogonum fasciculatum.
Photo going up on MWHA Facebook page in the next few minutes.
Julian

Possibly Achmon Blue on Baccharis

The final butterfly species we were lucky enough to photograph today was an unidentified Grass Skipper in the family Hesperiinae, and they were also present in significant numbers.

Grass Skipper on Baccharis

Other visitors to the Baccharis that were spotted but not photographed include a Cabbage White, a Figeater, several Cactus Flies, a large Syrphid Fly and other flies.

 

 

 

 

 

 

 

Letter 21 – Yellow Angled Sulphur

 

Magnolia, TX – light green butterfly
Howdy!
I love taking pix of butterflies and I plant my flowerbeds
to attract them. Your awesome site is my favorite bug-n-butterfly
reference, but I haven’t been able to find this lovely
light green beauty. Do you know what it is? Magnolia
is north of Houston, near Conroe. Thanks bunches,
Kristi

Hi Kristi,
We believe this is the Yellow Angled Sulphur, Anteos maerula,
which we located on the Mariposas
Mexicanas website
.
Our Butterflies Through Binoculars
The West book by Jeffrey Glassberg shows it in the southernmost
tip of Texas, so it is possible its range is expanding, or
perhaps it has been blown north by recent storms. It might
also be a closely related species, the White Angled Sulphur,
Anteos clorinde, which is also pictured on the Mariposas
Mexicanas website
. Thanks for submitting a new species to our site.

Reader Emails

Over the years, our website, whatsthatbug.com has received hundreds of letters and some interesting images asking us about these insects. Scroll down to have a look at some of them.

Letter 1 – Cloudless Sulfur Caterpillar, we believe

 

Caterpillar ID
Location: Tampa, FL
November 4, 2011 3:34 pm
We are located in Tampa, FL. My neighbor found a tree full of these yellow w/ black stripes caterpillars.
Any ideas? What will they turn into?
Signature: Thanks, Heidi

Cloudless Sulfur Caterpillar, possibly

Hi Heidi,
We believe we have correctly identified your caterpillar as that of a Cloudless Sulfur butterfly,
Phoebis sennae, though the resolution on your photo prohibits definitive identification.  If you can provide the name of the tree or a description of the tree, it might help to confirm our identification.  The caterpillars of the Cloudless Sulfur feed on the leaves and blossoms of Cassia and related trees.  These trees generally have showy yellow flowers.  Here is a photo on Bugguide of a Cloudless Sulfur caterpillar on the food plant.

Letter 2 – Sulphur Caterpillar: Orange Barred Sulphur???

 

Lime Green Caterpillars munching on Cassia Tree
Thu, May 7, 2009 at 11:48 AM
I have been trying to identify the lime green caterpillars currently munching on my recently transplanted Cassia Excelsa Tree. I saw the pictures on your site referring to the Cloudless Sulpher caterpillar and how it can be yellow or green depending on it eating the leaves or the flowers of the Cassia but I don’t think they are Cloudless Sulphers.The body structure of the caterpillar pictures I am sending is similar to the Cloudless but the striping on the side is much different. The Cloudless Sulpher appears to have more of a black banding around it. The caterpillars I have look to have a black short stripe sandwiching four longer stripes and then another short stripe. Also the head of the caterpillar is the entirely lime green with no black at all.Thank you for help.
JRS
Tampa Bay Area – Florida

Orange Barred Sulphur Caterpillar
Orange Barred Sulphur Caterpillar

Dear JRS,
Your caterpillar is definitely a Sulphur in the genus Phoebis.  We believe it to be a close relative of the Cloudless Sulphur, the Orange Barred Sulphur, Phoebis philea.  There is a photo posted to BugGuide that looks very similar to your specimen.

Orange Barred Sulphur Caterpillar
Orange Barred Sulphur Caterpillar

Letter 3 – Cloudless Sulphur Caterpillar

 

pretty yellow caterpillars devouring my shrub
We’ve got lots of these guys all over a yellow flowering tree/shrub in our yard (not esperanza). We’ve never seen them before because this is the first year the tree/shrub is flowering. It had been in a dry, shady spot prior but this spring we moved it to a sunny area where it benefits from our sprinkler system and so now is flowering like crazy. And these guys have moved in and are busily munching away. What are they?
Northwest Austin Thank you!
Vicki

Cloudless Sulphur Caterpillar
Cloudless Sulphur Caterpillar

Hi Vicki,
Losing a few blossoms is a small price to pay for the reward of the numerous clear yellow, fast flying Cloudless Sulphur Butterflies, Phoebis sennae, that will fly about your garden after the metamorphosis is complete. Interestingly, Cloudless Sulphur caterpillars that feed on the leaves of Cassia are green, and those that feed on the flowers are yellow.

Letter 4 – Cloudless Sulphur Caterpillar from Brazil

 

Phoebis sennae marcellina
Location: Londrina-Paraná-BRASIL
April 9, 2012 2:54 pm
Phoebis sennae marcellina
Signature: Eduardo Lucof

Cloudless Sulphur Caterpillar

Hi again Eduardo,
Thank you for submitting your four caterpillar photos from Brazil.  We are posting the Cloudless Sulphur Caterpillar,
Phoebis sennae marcellina, and we will try to post others if time permits.  Cloudless Sulphurs are now residents in the Los Angeles area where the What’s That Bug? offices are located.  They are not native, but cultivation of their food plants, the cassia tree, in gardens has provided a source of food for the caterpillars enabling the species to establish itself.  We are linking to the Butterflies of America page on the Cloudless Sulphur.

Letter 5 – Clouded Skipper Caterpillar, we believe

 

Subject:  Caterpillar
Geographic location of the bug:  Cary NC
Date: 06/15/2021
Time: 03:56 PM EDT
Your letter to the bugman:  Found this little guy nibbling on my corn leaves. Would love to know what it is.
How you want your letter signed:  Winters

Probably Clouded Skipper Caterpillar

Dear Winters,
We believe based on this BugGuide image that you have a Clouded Skipper Caterpillar,
Lerema accius.  According to BugGuide:  “Caterpillars host on grasses” and since Corn is a grass, it is a possible food plant.  According to the Alabama Butterfly Atlas:  “The caterpillar is greenish-white with a mid-dorsal dark stripe and two white lateral stripes. The head is white with a black margin and three vertical black stripes on the facial region. The body is covered with numerous minute white dots.”

Probably Clouded Skipper Caterpillar

Letter 6 – Cloudless Sulphur

 

What type of sulphur butterfly is this?
Fri, Jan 16, 2009 at 11:29 AM
I took a picture of this butterfly while in South Florida on the edge of the Loxahatchee River. I would say the plants in the area are typical of south florida and or wetlands. I found various sulphur butterflies, but I could not find any that were the same green color and am hoping you could help me to identify it.
Madcalabrian
Riverbend Park, Jupiter Florida

Cloudless Sulphur
Cloudless Sulphur

Dear Madcalabrian,
This sure looks like a Cloudless Sulphur, Phoebis sennae, to us.  According to BugGuide, the Cloudless Sulphur may be identifiede by the following description:  “upperside of male wings lemon yellow or pale greenish-yellow with no markings; female forewing with small dark spot, usually a narrow blackish outer margin, and a few vague dark dots near tip. Underside of hindwing with two silver black-rimmed spots in both sexes.”  This butterfly breeds in the Southern states and strays north in the fall.

Letter 7 – Cloudless Sulphur

 

Subject: Yellow Butterfly
Location: West Los Angeles
October 9, 2016 4:11 pm
These have been around the backyard for years but they don’t usually sit still long enough to grab the camera to take a picture. This picture was taken 10-9-16 in in West Los Angeles area. The flower is a Cape Marigold and this particular butterfly seems attracted to only the yellow flowers of that plant.
Signature: Phil Hackett

Cloudless Sulphur
Cloudless Sulphur

Hi Phil,
This is one of the Sulphur butterflies in the genus
Phoebis, and we are pretty certain it is the Cloudless Sulphur, Phoebis sennae.  This is a very fast flying species, and it is our experience that they are difficult to approach, so your images are a marvelous addition to our site.  According to BugGuide:  “upperside of male wings lemon yellow or pale greenish-yellow with no markings; female forewing with small dark spot, usually a narrow blackish outer margin, and a few vague dark dots near tip. Underside of hindwing with two silver black-rimmed spots in both sexes.”

Cloudless Sulphur
Cloudless Sulphur

Letter 8 – Cloudless Sulphur Puddling in the heat

 

Subject: Cloudless Sulphur puddling
Geographic location of the bug:  Mount Washington, Los Angeles, California
Date: 07/06/2018
Time: 05:15 PM EDT
Last week when temperatures in Los Angeles reached triple digits, Daniel was watering and he was lucky enough to be able to approach a normally very wary and fast flying Cloudless Sulphur as it puddled at the mud created by the hose.

Cloudless Sulphur

 

Letter 9 – Cloudless Sulphur Caterpillar

 

what is this caterpillar?
Hi Bugman,
I found this caterpillar in Santa Barbara, California. I found it interesting that it matched the color of the plant I found it on. I have looked around a bit on the web to identify it without any luck. Can you help? Also, any idea which plant it is eating? Thank you!!
Dan Sullivan

Hi Dan,
This is a Cloudless Sulphur Caterpillar, Phoebis sennae, also called the Senna Sulphur. The butterfly is a large, clear yellow, fast flying species. The plant is Senna. As a means of camouflage, the caterpillars are often green when feeding on the leaves, and yellow when feeding on the blossoms.

Letter 10 – Cloudless Sulphur Caterpillar

 

Subject: Yellow caterpillar Tucson AZ
Location: Oro Valley, AZ on Narana Road
October 9, 2015 11:50 am
What does this caterpillar become?
Signature: Curious

Cloudless Sulphur Caterpillar
Cloudless Sulphur Caterpillar

Dear Curious,
This is the caterpillar of a Cloudless Sulphur butterfly,
Phoebis sennae, and the caterpillars have both green and yellow forms.  The adult Cloudless Sulphur is a beautiful yellow butterfly.  According to BugGuide:  “Caterpillar feeds most commonly on Cassia and some other woody and herbaceous legumes.”  Interestingly, the yellow caterpillars are quite well camouflaged when feeding on the yellow flowers of the plants and the green caterpillars are well camouflaged when feeding on the leaves.  It is our theory that the green caterpillars feeding on the flowers were eaten by birds and the yellow caterpillars feeding on leaves were eaten by birds, and not that the caterpillars are able to change color when feeding on either flowers or leaves.  We have a nice series of images of the metamorphosis of the Cloudless Sulphur in our archives.

Thank you
Liane Futch

Letter 11 – Cloudless Sulphur Caterpillar

 

Subject:  Cloudless Sulphur Caterpillar in Mount Washington
Location:  Mount Washington, Los Angeles, California
February 28, 2016
We were shocked to see this bright yellow caterpillar meandering across the patio.  We immediately recognized a Cloudless Sulphur Caterpillar,
Phoebis sennae, but we do not have any Cassia growing anywhere near.  Where did it come from?  We checked BugGuide and learned:  “Caterpillar: usually pale green and marked by a yellow stripe on each side and black spots in rows across each abdominal segment.  Above and below the yellow stripe there are usually small areas marked with blue.   There is also a yellow form that occurs when it feeds on yellow flowers of its host plants. The later instars of the yellow form have a dark transverse band across each segment” which means our Caterpillar was feeding on yellow blooms.  According to BugGuide:  “Caterpillar feeds most commonly on Cassia and some other woody and herbaceous legumes” and we do have an Acacia in the garden, another legume in the family Fabaceae , so we will check it out to see if there are any additional Cloudless Sulphur Caterpillars feeding upon it.

Cloudless Sulphur Caterpillar
Cloudless Sulphur Caterpillar
Cloudless Sulphur Caterpillar
Cloudless Sulphur Caterpillar

Letter 12 – Cloudless Sulphur Caterpillar

 

Subject: identification
Location: Tucson, AZ
October 6, 2016 6:04 pm
Dear Bugman,
I am submitting a few photos of insects for identification. They were taken between October 1 and 4 2016 in our community garden in Tucson, AZ.
Image 1 I believe to be a bee fly, perhaps of genus Exoprosopa.
Image 2. is a caterpillar (Sulphur of some sort?) on Lindheimers Senna
Image 3 fairly large sized ants
I would be very happy if you could identify the insets in these photos that I would like to share with my fellow gardeners.
Thanks very much!
Signature: Melody

Cloudless Sulphur Caterpillar
Cloudless Sulphur Caterpillar

Dear Melody,
Unless there is a good reason, like a predator/prey relationship, we tend to confine our postings to a single species, or closely related species for classification purposes on our site.  We will be dealing with your identification requests one at a time.  The caterpillar is that of a Cloudless Sulphur,
Phoebis sennae, which you can verify by comparing your image to this BugGuide image.  The caterpillars are found in both a yellow and green form, with the yellow caterpillars feeding on blossoms and the green ones feeding on leaves.

Letter 13 – Cloudless Sulphur Caterpillars (or possibly Orange-Barred Sulphur)

 

Caterpillars on Cassia
I found these two on my cassia last week. I think the one with stripes running the length is a sulphur of some kind. Any idea about the other one?
Donna Williams
DeLand, Florida

Hi Donna,
We are pretty certain both of your caterpillars are the same species, the Cloudless Sulphur, Phoebis sennae, a beautiful, swift flying, shrome yellow butterfly. BugGuide pictures two color forms of the caterpillar, green with longitudinal stripes, and yellow with traverse stripes. The yellow form is reportedly more common when the caterpillar feeds on flowers, but both of your specimens seems to be feeding on the flowers.

Sulphurs (11/16/2006)
Hey Guys, The pic on the right could also be Orange barred sulphur (Phoebis philea). I’ve seen then both feeding on species of Cassia and Senna in Southern Florida. Sometimes they feed on the same plant. We have them both here on the Gulf Coast of Texas, as well. I took a few of each and raised them, and when they’re in the Yellow/flower eating from they look alot alike. Just wanted to share. Eric Duran
Nature Discovery Center
Bellaire, TX

Letter 14 – Cloudless Sulphur Chrysalis

 

Can you ID me?
Hi Bugman,
Can you please help me identify this “thing”…. I live in Coconut Creek, Florida and saw this on one of my Jasmine plants that I recently brought home from the nursery (bonus!!). I’ve searched the internet far and wide but … just haven’t come across anything that looks like this. Can you help ID me? Thanks so much!
Debi
PS – LOVE your website.

Hi Debi,
This is the Chrysalis of a large yellow butterfly known as the Cloudless Sulphur, Phoebis sennae, sometimes called the Senna Sulphur, though it might also be from a close relative, the Orange Barred Sulphur, Phoebis philea.

Update on Comment: 
Dead Chrysalis
November 7, 2011 8:47 am
Of course I could be wrong, but after having raised thousands of sulphurs, the color isn’t right.  The dark spot where the pupa narrows is one sign.  The general color is another.  Normally they are one color pretty much all over.
http://www.butterflyfunfacts.com/images/cloudlesssulphur5colorpupae6.jpg Brown in these pupae is a bad sign.  Yellow wings show through, not beige or brown.  There can be a coral colored chrysalis but not this ‘dirty’ look.
http://www.butterflyfunfacts.com/images/cloudlesssulphurchrysalisorange6.jpg  I learn more everytime I visit your site.  Thank you!
Signature: Edith Smith

Letter 15 – Female Clouded Sulphur

 

What is this butterfly?
October 8, 2009
This butterfly has black edges and the rest is yellow other than one black spot on each upper wing and one yellow spot on each lower wing. I would really just like the scientific name.
scientific name?
Manchester, NH

Clouded Sulphur
Clouded Sulphur

Dear scientific name?
This is a Sulphur Butterfly in the genus Colias.  We believe it is a female Clouded Sulphur, Colias philodice.  It is the white form of the female, a common variation.  Both the Clouded Sulphur and the Orange Sulphur, Colias eurytheme, have a white form female.  According to BugGuide, the best way to distinguish the two from one another is:  “The white form female philodice can often be separated from the white form female eurytheme by the HW outer margin. In philodice the HW outer margin will have a more narrow smoother solid black border, while eurytheme most often has an irregular and wider black border, many times with diffuse white markings within the black border.
”  BugGuide also has photos that illustrate this difference.  Actually, upon closer inspection, we believe this to be the typical yellow form of the female Clouded Sulphur.  The female can be distinguished from the male in that the black borders on the wings of the female have spots, and the male has solid black borders.

Letter 16 – Male Cloudless Sulphur

 

Subject: Another Sulphur Butterfly 🙂
Location: Coryell County, Texas
October 10, 2016 8:32 pm
Another morning of gardening, another beautiful yellow butterfly visiting the Autumn Sage (Salvia greggii). I wish I could capture how beautiful these butterflies are! It’s tough for me to get the yellows and whites to show as more than bright blurs in the sunshine.
I think this is another Sulphur, but can’t tell which species.
Such gorgeous weather, 70’s to 80’s, no rain this week.
Thank you for all of your help throughout the months, seasons and years!
Signature: Ellen

Male Cloudless Sulphur
Male Cloudless Sulphur

Dear Ellen,
This individual is a male Cloudless Sulphur,
Phoebis sennae, which you can verify by comparing to this BugGuide image.  Interestingly, it appears to be nectaring from the same type of sage plant.  According to BugGuide:  “upperside of male wings lemon yellow or pale greenish-yellow with no markings; female forewing with small dark spot, usually a narrow blackish outer margin, and a few vague dark dots near tip. Underside of hindwing with two silver black-rimmed spots in both sexes.”  Your one image nicely illustrates the “male wings lemon yellow or pale greenish-yellow with no markings.”  We suspect the appearance of this male Cloudless Sulphur is a good indication that the image you submitted last week is a female Cloudless Sulphur.  Butterflies in motion can be difficult to capture in images, but we think you are doing a marvelous job and your images are a good indication of the patience you have with your uncooperative subjects.  

Male Cloudless Sulphur
Male Cloudless Sulphur

Letter 17 – Sulphur Butterfly

 

Butterfly
Location:  Columbia SC
October 2, 2010 12:57 pm
My cousin sent me this picture. It was recently taken (early fall). It is such a pretty color and I’d like to be able to identify it. Please help. Thank you
Signature:  Brenda

Sulphur Butterfly

Hi Brenda,
We are able to provide you with a genus, but an exact species may be difficult as all the Sulphurs in the genus
Colias look rather similar on the undersides.  You may scan the possibilities on BugGuide to see what we mean.  Your photo is somewhat disturbing.  Something just doesn’t seem right to us.  We can’t help but wonder if perhaps this lovely Sulphur has become a meal for an unseen predator, more specifically a Crab Spider or Flower Spider.  Crab Spiders wait on blossoms to ambush pollinating insects.  something about the way the bloom has engulfed the butterfly has lead us in that supposition.

Letter 18 – Sulphur Caterpillar

 

Probably so simple — what’s this caterpillar?
Hi, Bugman — it’s 2:08 a.m. and I’ve been looking through your website for a couple of hours. I really ought to be trying to get some sleep — I am a stay-at-home Dad of 19-month old twins — but the site is fascinating. When a question about a furry caterpillar’s identification came up at the playground today, I gave two people your web address. I have seen these caterpillars before but never photographed any until tonight. I didn’t see anything quite the same on your site, so I’d like your help. Any thoughts? My wife and I live in Arlington, Va, in case that’s helpful. Many thanks for a great site and lots of interesting photos and information.
Thanks again for hours of fun.
David Foose

Hi David,
If you only knew about the hours we spent on our site instead of sleeping. This appears to be a Sulphur Butterfly Caterpillar in the genus Colias. Caterpillars feed on clover, alfalfa and other legumes.

Letter 19 – Female Cloudless Sulphur, we believe

 

Subject: Yellow Butterfly, a Cloudless Sulphur, perhaps?
Location: Coryell County
October 8, 2016 7:04 pm
Hello again!
Many butterflies today. I think this may be a Cloudless Sulphur (Phoebis sennae), but I’m not sure. Thes are quite large, and only visit the salvia greggi (Autumn sage), ignoring the other flowers in the garden. I believe you identified a similar butterfly for me several years ago, thank you!
Best wishes for a great autumn!
Signature: ellen

Sulphur, but which species?
Probably Female Cloudless Sulphur

Dear Ellen,
You are correct that this is a Sulphur in the genus
Pheobis, but we cannot say for certain which species.  Your individual does resemble the Cloudless Sulphur in this BugGuide image, but it also resembles this Orange Barred Sulphur, also pictured on BugGuide.  Unfortunately, the open-winged image you provided is lacking in critical detail.

Update
Subject: Sulphur: Cloudless or Orange-Barred? Part II
Location: Coryell County, TX
October 10, 2016 9:17 pm
Hello again! Thank you for your quick response. I saw the entry of the Cloudless Sulphur from Los Angeles, so beautiful.
I found this article on Orange-Barred Sulphurs (found now in California) and thought it was so interesting: http://www.monarchprogram.org/new-butterfly-species-in-the-southwest-the-orange-barred-sulfur-phoebis-philea/
I looked back at my photos and realized that, although too blurry, these show the sunlit color of the butterfly in question. It was lemon yellow, no orange that I ever spotted; I don’t know if that makes a difference or not. Gorgeous butterfly on the wing. Will keep trying to get clearer photos of the insects in our gardens.
Love your site! Thank you so much for all of the information.
Signature: Ellen

Cloudless Sulphur
Cloudless Sulphur

Hi again Ellen,
Thanks for the update.  We believe based on the images you just submitted of a male Cloudless Sulphur, that this is a female of the species.

Letter 20 – What’s Buzzing The Baccharis in Elyria Canyon Park??? Achmon Blue and others

 

The Baccharis that is blooming in Elyria Canyon Park is attracting a myriad of insects in search of nectar.
Location:  Elyria Canyon Park, Mount Washington, Los Angeles, CA
September 30, 2012

Baccharis near Red Barn in Elyria Canyon Park

The hedge of native Baccharis near the Red Barn in Elyria Canyon Park is about ten feet tall and it is currently in bloom.  There is a noticeable buzzing one hears upon approach, and that is caused by thousands of Honey Bees eagerly gathering nectar.  It seems Baccharis is a magnet for pollinating insects of all types, and without a doubt, the Honey Bees are the most numerous, but other insects can be spotted taking advantage of the bounty.

Honey Bees on Baccharis

Clare and Daniel made a trip on Saturday and though there was work to be done, Daniel used Clare’s camera to get a few photos.  The largest butterfly spotted on the Baccharis was a Painted Lady, Vanessa cardui, butDaniel was unable to get a photo with a spread wing view.

Painted Lady on Baccharis

Though the photo is quite out of focus, Daniel also managed to get a photo of this Checkered Skipper in the genus Pyrgus that did not want to hold still long enough to be photographed.

Checkered Skipper on Baccharis

A tiny creamy yellow butterfly was observed flying close to the ground, but it never landed, so no conclusive identification could be made.  Daniel returned today with a better camera and decided to document the visitors to the Baccharis.  A 50mm lens with a macro feature allowed for closeup photographs, however, since there was no zoom, the photographer often startled the insect subjects into flying away.  Luckily the tiny yellow butterfly made a return appearance and posed for two quick photos.  These photos substantiated a sighting local lepidopterist Julian Donahue made on August 23 of a Dainty Sulphur, Nathalis iole, though it is doubtful the individual Julian spotted over a month ago at his home is the same individual photographed in Elyria Canyon Park, which would indicate there may be a local population with noticeable numbers present in Mount Washington this summer.

Dainty Sulphur on Baccharis

There were at least three species of Gossamer Winged Butterflies present today, and the largest were the Gray Hairstreaks, Strymon melinus.  These little beauties have the habit of rubbing their hind wings together, perhaps to attract the attention of any predator into mistaking the tail and wing spots for the head of the butterfly and deflecting an attack from the vital organs to the expendable wings.

Gray Hairstreak and Honey Bee on Baccharis

Smaller than the Gray Hairstreak is another Gossamer Wing, the Marine Blue, Leptotes marina.  They were present in sufficient numbers to flutter about in small groups.

Marine Blue on Baccharis

The smallest of the Gossamer Winged Butterflies were another species of Blue, possibly the Achmon Blue, Plebejus acmon, though we are still awaiting Julian’s input on that identification.

Confirmation from Julian Donahue
NEW to the Mt. Washington Butterfly List! Good job, Daniel.
Although this is a tough group of butterflies to identify, it appears to be an Acmon Blue (Icaricia acmon). Larvae feed on Deerweed (Lotus scoparius, now Acmispon glaber) and Astragalus (none of this in Elyria that I know of); also on California Buckwheat, Eriogonum fasciculatum.
Photo going up on MWHA Facebook page in the next few minutes.
Julian

Possibly Achmon Blue on Baccharis

The final butterfly species we were lucky enough to photograph today was an unidentified Grass Skipper in the family Hesperiinae, and they were also present in significant numbers.

Grass Skipper on Baccharis

Other visitors to the Baccharis that were spotted but not photographed include a Cabbage White, a Figeater, several Cactus Flies, a large Syrphid Fly and other flies.

 

 

 

 

 

 

 

Letter 21 – Yellow Angled Sulphur

 

Magnolia, TX – light green butterfly
Howdy!
I love taking pix of butterflies and I plant my flowerbeds
to attract them. Your awesome site is my favorite bug-n-butterfly
reference, but I haven’t been able to find this lovely
light green beauty. Do you know what it is? Magnolia
is north of Houston, near Conroe. Thanks bunches,
Kristi

Hi Kristi,
We believe this is the Yellow Angled Sulphur, Anteos maerula,
which we located on the Mariposas
Mexicanas website
.
Our Butterflies Through Binoculars
The West book by Jeffrey Glassberg shows it in the southernmost
tip of Texas, so it is possible its range is expanding, or
perhaps it has been blown north by recent storms. It might
also be a closely related species, the White Angled Sulphur,
Anteos clorinde, which is also pictured on the Mariposas
Mexicanas website
. Thanks for submitting a new species to our site.

Authors

    by
  • Bugman

    Bugman aka Daniel Marlos has been identifying bugs since 1999. whatsthatbug.com is his passion project and it has helped millions of readers identify the bug that has been bugging them for over two decades. You can reach out to him through our Contact Page.

  • Piyushi Dhir

    Piyushi is a nature lover, blogger and traveler at heart. She lives in beautiful Canada with her family. Piyushi is an animal lover and loves to write about all creatures.

17 thoughts on “Cloudless Sulphur: All You Need to Know for Butterfly Enthusiasts”

  1. When you first identified the little guys for me, I googled them and saw all these photos of bright green caterpillars. I was thinking “But my guys are bright yellow – they don’t look the same!”. Thanks for clearing it up for me – I have flower-munchers. And lots of them!! Luckily my cassia is in massive bloom so I don’t mind sharing it with the caterpillars.

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  2. hey! where did they go? my cassia was full of them and today i checked and they are gone (as are all the cassia flowers) but no chrysalises! i was expecting to enjoy watching to whole process but they chewed and blew outta dodge. ingrates!

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  3. Hi Veek,
    Perhaps your caterpillars left in mass to find a good location for pupation. Caterpillars often leave the food plant and seek shelter elsewhere.

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  4. my son found one we put it in an open top jar it made its way into a corner and immediately turned into a green and orange cocoon . we’ve had it almost a week and are wondering how long until it hatches.

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  5. We found a whole group of the cloudless sulphur caterpillar on our small cassia plant that we bought in Palm Springs a few years ago.

    We are wondering what it will look like as a butterfly. I guess we will look up the same name but in a butterfly. Oh, yes are they a harm to our plant because we would hate to have to relocate them. Also, will they cocoon on the Cassia or move to a more private area?

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  6. We found a whole group of the cloudless sulphur caterpillar on our small cassia plant that we bought in Palm Springs a few years ago.

    We are wondering what it will look like as a butterfly. I guess we will look up the same name but in a butterfly. Oh, yes are they a harm to our plant because we would hate to have to relocate them. Also, will they cocoon on the Cassia or move to a more private area?

    Reply
  7. Hi! I just found this same caterpillar on my new Cassia tree. Should I leave it alone, or will it strip the tree of the blooms and leaves? ☹️

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    • You would need to have 1000s of caterpillars to strip the trees. A few won’t even be noticed, and you will have some showy yellow butterflies as a result.

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  8. I planted a Cassia Popcorn tree a couple of months ago and I already have a Cloudless Sulfur caterpillar eating the yellow flowers (the caterpillar is a beautiful yellow). I have raised Swallowtails and Monarchs in my lanai inside a butterfly net. What can I feed this guy to keep him inside?

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