Currently viewing the category: "Inchworms"

Subject: Colorado Caterpillar
Location: 11 mile Canyon outside of Lake George, Colorado
June 23, 2016 8:10 am
Hey Bugman!
I have no idea what kind of caterpillar this is! Or what kind of moth/butterfly it will become. I tried all of my bug books and online resources.
This little guy was found in 11 mile Canyon in Colorado.
Thank you!
Signature: Frankie

Barberry Geometer

Colorful Inchworm:  Meris alticola perhaps

Dear Frankie,
Because of the reduced number of prolegs, your caterpillar is easily identified as an Inchworm or Spanworm in the family Geometridae, though its colorful markings make it unusual in that family, most of whose members have caterpillars that are green or brown and effectively mimic twigs.  At first we thought we had correctly identified your Inchworm as a Barberry Looper or Barberry Geometer,
Coryphista meadii, based on this BugGuide image, but we remembered identifying a similar Inchworm in the past and we could not find one in our archives.  We searched our archives for “colorful Inchworm” and we found this posting of Meris paradoxa that looks possible as well, but the species is only reported from Southern Arizona according to BugGuide.  The related and similar looking Meris alticola is also pictured on BugGuide, and it is reported on BugGuide from Colorado, so of the three, our money is on Meris alticola

Subject: Caterpillar/Inchworm Michigan
Location: Redford, Michigan
May 31, 2016 6:40 am
Dear Bugman,
This little caterpillar fell on my arm, while I was sitting under a Black Walnut Tree in southeastern Michigan on 5/28/2016. He was quite small, maybe inch long and a quarter inch wide.
Thank you for the service you provide.
Signature: Kristin

Filament Bearer

Filament Bearer

Dear Kristin,
This Inchworm is one of the Filament Bearers in the genus
Nematocampa, an identification that can be verified on BugGuide.

Subject: Caterpillar id
Location: Big Lake, Minnesota
May 30, 2016 3:29 am
Good morning. My sister has caterpillars in her semi woodland garden in Big Lake Minnesota that are literally dropping from the trees (pine and ornamentals) on the margin of the woodland. They seem to be most active now – mid May. It is her first summer there so cannot say whether this is unusual.
Signature: Lorna

Ed. Note:  We had an offline exchange with Lorna since the image attached to the original email was a Black Arches Caterpillar from our site.  We finally received the correct image.

Oops. I don’t know how that happened – I am sorry. Here it is:

Inchworms dropping from trees

Cankerworm dropping from trees

Dear Lorna,
The general term Cankerworm is used to describe several species of Inchworms or Spanworms that feed in trees and drop to the ground.  According to Virginia Green Lawn Care:  “The term ‘canker worm’ is used, not to describe a single caterpillar, but a group of inchworms that cause damage to many different ornamental and fruit trees. … These leaf eating insects are not only a nuisance; they can cause great damage or even destroy a grown tree over a period of time. You may have run into one dangling from a silk thread as you walked under a tree. It is a battle between canker worms and the trees you love and have planted and nurtured.  When heavy populations are present, they can completely defoliate a tree in just a few weeks. This is when you need to step in.”  The individual in the new image you attached looks like the Linden Looper,
Erannis tiliaria, a species that according to BugGuide feeds on:  “Deciduous trees, including apple, ash, beech, birch, elm, maple, oak, poplar, Prunus and Ribes.”

Subject: Ugliest caterpillar
Location: Southeast Michigan
July 17, 2015 8:38 am
I found this in someone’s garden while i was working. What type of moth or butteffly might it be? I have never seen anything like it before.
Signature: – ruth the gardener



Dear Ruth the gardener,
This is an Inchworm or Spanworm in the family Geometridae, and larvae can often be very difficult to identify to the species level.  One of the most noticeable features on your Spanworm is the red color of the spiracles or breathing openings on the side.  We thought that might lead us to an identification, but alas, it did not.  Knowing the plant the Spanworm was feeding upon might help.  Though we can make out a leaf on the right, we cannot tell the identity of the plant.  If you can supply us with the plant, we might have better luck.

Subject: Bug identification
Location: Bowling Green, Ohio USA
May 24, 2015 2:47 pm
I found this bug crawling on my shoulder and have never seen one that looks like this. I live in Bowling Green, Ohio and was curious what it is. I heard about a kind of caterpillar that will bite and leave welts. I have children and want to make sure this bug is not harmful. Thank you so much in advance.
Signature: Stephanie P

Filament Bearer

Filament Bearer

Dear Stephanie,
This Inchworm in the family Geometridae is a Filament Bearer or Horned Spanworm in the genus
Nematocampa which you can verify on BugGuide.  In our opinion, this is not a harmful species.

Thank you so much for the speedy answer! I feel a lot better now that I know what it is and that it is harmless! Stephanie

Subject: Inchworm Mayhem
Location: Mumbai, India
April 29, 2015 7:34 am
Dear Bugman,
These inchworms have wreaked havoc in my tiny balcony garden, fairly shredding my spider-plants to bits. Could you help id? I understand from your site that inchworms are geometrid moths caterpillars. It’s full summer now in India, and the photos are today’s (April 29). Another couple of days and it would’ve been ‘May’hem quite literally and figuratively 😀
Signature: Ankush



Dear Ankush,
Is your Spider Plant a Chlorophytum species like that posted on Wikipedia?  Knowing the food plant is often a big help with identifying caterpillars and other plant feeding insects.  We attempted a search with the genus name of the Spider Plant and the family name Geometridae, but to no avail.  You image is stunning and clearly shows the looping action the Inchworm uses to move about, a result of having fewer sets of prolegs than the typical caterpillar.