Emesinae: All You Need to Know About These Unique Insects

Emesinae, commonly known as thread-legged bugs, are a subfamily of fascinating predatory insects belonging to the Reduviidae family. These slender and delicate insects are characterized by their long, thread-like legs and elongated bodies. They can be found in various habitats, such as leaf litter, tree bark, and foliage, where they hunt other small invertebrates for food.

One key feature of Emesinae is their specialized raptorial forelimbs, similar to those of praying mantises, which they use to capture and hold their prey. These adept predators can move quickly through their environment and even exhibit impressive climbing abilities. Their life cycle typically consists of eggs, nymph stages, and a final adult stage.

Emesinae examples include species of the genera Emesaya, Stenolemus, and Ploiaria. When it comes to recognizing different species, a comparison table can be useful:

By understanding the diverse world of Emesinae, we can appreciate the intricacies of these elusive predatory insects and their unique adaptations in nature.

Emesinae: Overview

Characteristics

Emesinae, also known as thread-legged bugs, are a subfamily of insects belonging to the Reduviidae family. These insects have a few distinct features:

• Slender body: Emesinae possess a long, thin body structure, making them easily recognizable among other insects.
• Long, thin legs: Their legs are exceptionally long and slender, which is why they are called thread-legged bugs.

Thread-Legged Bugs

Thread-legged bugs are a fascinating group of insects within the Emesinae subfamily. Some unique aspects include:

• Predatory nature: They are predators, primarily preying on other small insects and arthropods.
• Habitat: These bugs are commonly found in various environments, such as foliage, tree trunks, and even under stones.

Here’s a comparison between Emesinae (thread-legged bugs) and other similar insects:

In summary, Emesinae, or thread-legged bugs, are unique insects with a slender body and long, thin legs. They are predatory in nature and can be found in a variety of habitats.

Taxonomy and Classification

Hemiptera

Hemiptera is an order of insects, commonly known as true bugs. This order comprises:

• Over 80,000 species
• Diverse physical features
• Piercing-sucking mouthparts

Examples of Hemiptera include aphids, cicadas, and stink bugs.

Heteroptera

Heteroptera is a suborder within Hemiptera, characterized by:

• Wing structure difference
• Incomplete metamorphosis

Two examples of Heteroptera species are water striders and shield bugs.

Reduviidae

Reduviidae is a family within Heteroptera, consisting of assassin bugs, which are:

• Predatory insects
• Equipped with a strong beak for attacking prey

Some well-known species in this family include the kissing bug and the wheel bug.

Subtribes within Emesinae

Emesinae is a subfamily of the Reduviidae family, consisting of several subtribes:

• Collartidini
• Leistarchini
• Emesini
• Deliastini
• Metapterini

These subtribes have distinct characteristics, as detailed in the comparison table below:

By understanding the taxonomy and classification of Emesinae, it becomes easier to identify the key characteristics, behaviors, and differences among these intriguing insects.

Geographical Distribution and Habitat

Diversity

Emesinae is a subfamily of insects within the Reduviidae family, known for their diverse distribution. They can be found in various environments, including:

• Forests
• Grasslands
• Caves

The diversity of Emesinae species is attributed to their adaptability and unique biology.

Tropics

Emesinae insects are predominantly found in tropical regions. Some examples of tropical locations with Emesinae populations include:

• Southeast Asia
• Central and South America
• Africa

Their preference for warm, humid environments allows them to thrive in these regions.

Geography

Emesinae species’ distribution is influenced by geography. Certain features, such as vegetation and climate, play a significant role in their habitat preferences. Here’s a comparison table of the geographical features affecting Emesinae distribution:

Understanding the geographical distribution and habitat preferences of Emesinae species is essential for effective conservation efforts and future studies in entomology.

Natural History and Behavior

Emesinae, also known as thread-legged bugs, belong to the family Reduviidae in the class Insecta. They are part of the phylum Arthropoda, which includes insects, crustaceans, and arachnids. Emesinae have a unique natural history and exhibit interesting behaviors.

Natural history:

• Part of the class Insecta
• Belong to the family Reduviidae
• Diverse group with over 300 species

These small predators are found in a wide range of habitats, such as leaf litter, tree trunks, and cracks. There are two tribes within Emesinae: Ploiariolini and Saicinae. They differ in aspects such as leg structure and prey capture methods.

Comparison of Ploiariolini and Saicinae:

Emesinae are known for their thread-like legs, which help them move and capture prey. They primarily feed on small arthropods, including spiders and other insects.

Feeding preferences:

• Small arthropods
• Spiders
• Insects

For example, Emesopsis infenestra is an arboreal species found in North America. It preys on spiders and hangs upside down from threads of silk to capture them.

Emesinae are not only fascinating due to their natural history but also their unique behaviors. So, if you’re interested in exploring the diverse world of arthropods, Emesinae is a captivating group to investigate.

Resources and Expert Advice

BugGuide

BugGuide is an essential resource for anyone interested in Emesinae. This online platform provides:

• Accurate information on various species
• High-quality images for identification
• Expert advice from entomologists

For example, BugGuide offers information about the work of Wygodzinsky, a prominent entomologist who extensively studied Emesinae.

Naturalists

Connecting with local naturalists is a fantastic way to learn more about the diverse natural world of Emesinae. Naturalists can:

• Share personal observations
• Guide you in identification
• Offer advice on habitat conservation

Local naturalist groups or clubs often organize field trips, where you can gain hands-on experience and learn from experts directly.

Local Extension Office

Your Local Extension Office is another valuable resource for accurate information and expert professional advice. The office can help you:

• Identify local Emesinae species
• Learn about their habitats and behavior
• Get guidance for pest control (if applicable)

A comparison of these resources:

In summary, BugGuide, naturalists, and your local extension office are excellent resources for learning about Emesinae. Access reliable information and gain expert guidance as you explore this captivating group of insects.

Contributions and Licensing

Contributed Content

Emesinae, an insect group, attracts contributions from various sources, including academic institutions like Iowa State University. Researchers and enthusiasts can submit their findings, creating a diverse knowledge base. Here are some features of the contributed content:

• Scientifically accurate information
• Diverse perspectives
• Regular updates

Examples of contributions include articles on Emesinae behavior, identification guides, and photographic records.

Usage Information

You can access Emesinae content through various formats, such as web pages, printer-friendly versions, or downloadable PDFs. While browsing, users may encounter different usage restrictions:

• Free access and usage for non-commercial purposes
• Restrictions on modifications or distribution of the content
• Mandatory attribution of the source

For instance, you can use an article for your academic research, but you may need to cite the author and the source.

Terms and Conditions

Before using Emesinae content, review the site’s terms of use, privacy statement, and site map for a better understanding of your rights and obligations. Here’s a comparison table of common terms and conditions:

Always adhere to these conditions, and contact the site administrator if you need further clarification.

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 – Thread-Legged Bug

mantis?
Location: Lehigh County, Pennsylvania
November 18, 2011 9:50 am
Hi. I’ve been finding these insects on the average of about one per year. When I was a kid, I found a few on one bush and put some into an aquarium and found one eating a little moth one day, but I don’t know if it scavenged a dead one. They have a piercing or sucking mouth part. In this picture, one is on my left pinky, to give you an idea of size. When not using them to help walk, it will hold its front arms or legs straight out in front. No one has ever been able to identify this insect in all these years.
Signature: WS

Dear WS,
Though the raptorial front legs are reminiscent of those of a Preying Mantis, this Thread-Legged Bug is not closely related.  It is in the Assassin Bug subfamily Emesinae, and we suspect it is in the genus Emesaya based on photos posted to BugGuide.  Like [most] other Assassin Bugs, Thread-Legged Bugs are beneficial predators.

Emesaya it is !  Thanks for identifying the insect that I have been trying to identify for 30 years.  Now, I hear Assassin Bugs have a nasty bite; should I not be handling these bugs?  They seem so docile though.
WS

Some Assassin Bugs are more prone to biting humans than others.  We have not heard of anyone being bitten by a Thread Legged Bug.

Letter 2 – Thread Legged Bug

Mantid / looks like walking stick
Please let me know when you have seen the images and if you find the exact species name. Up close it looked exactly like a preying mantis with a head shaped slightly different. Thank you for your help,
Van Lavoy Jacobs 2
Frederick, MD

Hi again Van,
Thank you for allowing us to post your excellent photos of an amazing insect, a Thread Legged Bug.

Ed. Note: Eric Eaton just provided us with the following information, and Van has provided additional photos.
(11/11/2005) “I would need to know the size of the critter to tell you even what genus it might be in. If it is 30+ mm, then it has to be Emesaya brevipennis. If it is under that size, then it is probably a species of Empicoris or Barce. I didn’t check to see where the image was shot, as there could be more possibilities in the southern U.S. Eric”

Letter 3 – Thread Legged Bug

Mantid / looks like walking stick
Any Idea what this insect is? It looks almost like a Grass-Like Mantid but its head isn’t shaped right. I have more photos from some other angles if you need them.
Van Lavoy Jacobs 2
Frederick, MD

Hi Van,
First we appologize for the long delay. Our internet access went down the day you sent this in. It was down for over a week and when our signal returned, our mailbox was to capacity with 477 letters. We have been posting recent letters and getting to the oldest last. We are THRILLED with your image, a new species for us. This is a Thread Legged Bug, one of the Assassin Bugs in the subfamily Emesinae. According to BugGuide, images on the web are rare, so we are honored to post yours. We would also like to see your other images and perhaps add them to BugGuide’s archive if you don’t mind. We might even be able to get you a species name.

(11/11/2005)
I would be glad to send any of the other images I have as well as a video you can download of him walking on my arm. We live in Keymar MD which may help you in the identification. Let me know if you would like a link to more pictures and video.
Van

Ed. Note: Eric Eaton just provided us with the following information, and Van has provided additional photos.
(11/11/2005) “I would need to know the size of the critter to tell you even what genus it might be in. If it is 30+ mm, then it has to be Emesaya brevipennis. If it is under that size, then it is probably a species of Empicoris or Barce. I didn’t check to see where the image was shot, as there could be more possibilities in the southern U.S. Eric”

Letter 4 – Thread Legged Bug

Walking Stick?
Hello from Wichita!….found this guy early Oct. and was wondering if he is a walking stick? Found it interesting that he has preying mantis like "arms"….love your site… thanks
Carrie

Hi Carrie,
Your fascinating insect is called a Thread Legged Bug. Thread Legged Bugs are Assassin Bugs that have been given their own subfamily: Emesinae. Based on the size of your specimen, it must be in the genus Emesaya, probably Emesaya brevipennis which can be found on BugGuide.

Letter 5 – Thread Legged Bug

Walking stick identity
We found this insect inside our house. It appears to be a walking stick, but much smaller and finer than the ones we usually see. It is a little over two inches long including its folded legs in front. It has light colored speckles/stripes on its back sets of legs. Could you tell me what species it might be? We are in Asheville, NC in the Blue Ridge Mountains. Thank you,
Angie

Hi Angie,
This is a Thread Legged Bug in the Assassin Bug subfamily Emesinae, probably Emesaya brevipennis.

Letter 6 – Thread-Legged Bug

Unknown micro-mantis
Hello Bugman!
I just wanted to ask for help with this tiny tiny critter. My friend found this inside of a cicada husk while collecting them for me in south central Pennsylvania. It was surrounded by some sort of webbing (or the husk was anyway), so at first we thought it was some sort of spider, but it only has six legs. It holds its two front limbs like a mantis, so I assume this is predatory. Any help would be appreciated! Thanks!
PS- I figured out my last mystery insect, it was a lesser ichneumon.
Blanton A.
Pennsylvania (Lancaster)

Hi Blanton,
We are happy you figured out your last mystery insect as we don’t have time to answer all inquiries. October 2 was a slow letter day, probably because many people were watching the debate. This is a predatory Thread-Legged Bug, most likely Stenolemus lanipes which can be found on BugGuide which indicates that it “Preys on spiders, or perhaps scavenges prey caught in webs.”

Letter 7 – Thread Legged Bug

Walkingstick look-alike
Fri, Nov 7, 2008 at 9:22 AM
Hello! I’ve been a fan for years and rec’d responses several times to my queries, and I thank you again for this great service you provide! I do not believe this insect is a true ‘Walkingstick’, but a look-alike. The legs were quite long, maybe 4-5″, antenna abt. 4″ and wings abt 1 1/2-2″ in length. I saw a photo similar to this insect somewhere with a diff. name and forgot to make note of it! =-( I was in a small field surrounded by woods when it came ‘floating’ very gracefully by. Fortunately, it landed just a few feet away, and I was able to get sev. diff poses of it. Any info you can provide is greatly appreciated. I am sending several captures for your best chance at ID’ing.
Thank you again for your time and service…you are very much appreciated!
Pat Garner, Hawk Point, MO
Lincoln Co., Hawk Point, MO abt 1hr 20 mins West of St. Louis, MO

Hi Pat,
Thank you for your sweet letter.  This is a Thread Legged Bug, an Assassin bug in the subfamily Emesinae.  We are relatively certain it is in the genus Emesaya, possibly Emesaya brevipennis which can be found on BugGuide.  Like all Assassin Bugs, they are predatory.

Letter 8 – Thread Legged Bug

Mini Praying Mantis
October 30, 2009
Hi,
My cat first found one of these interesting creatures inside our house (7/6/09), and I made a short video of it before letting it go: http://www.youtube.com/watch?v=xoISwh7K8BE
Last night (10/29/09), in my cat’s water dish, I rescued another one (or the same one) from the water. It seems similar to the grass mantis (four spider-like legs), but both the head and body shape are clearly different. What do you think?
Best wishes,
Rich
Rich Smith / RichSmith.com / Los Angeles
West Los Angeles 90066

Hi Rich,
This is an Assassin Bug in the subfamily Emesinae, known as the Thread Legged Bugs.  Our best guess is that it is in the genus Empicoris, characterized by “femora, tibiae, and antennae banded black and white; forefemora thickened, elongate; wings slender, extending slightly beyond tip of abdomen” according to BugGuide.  The front legs that are modified for grasping insects do resemble the front legs of mantids.

Letter 9 – Thread Legged Bug

Possible Phasmid?
Location: Upstate New York
January 24, 2012 12:11 pm
We saw this guy in our hedges last summer around mid July. It had two tiny wings and could fly, but not very fast. It also had tiny vice-like forearms, similar to a mantid. I tried looking this up online but can’t seem to definitively identify this bug.
Signature: lureah21

Dear lureah21,
Though it somewhat resembles a Phasmid, it is not.  Your observation of the raptorial forelegs was keen, identifying this as a predator and not a vegan.  Your insect is a True Bug in the Assassin Bug family.  It is subclassified as a Thread-Legged Bug in the subfamily Emesinae.  We believe it is most likely in the genus Emesaya, possibly Emesaya brevipennis which you can find on BugGuide.

Thank you for your response, that does appear to be the bug we saw.
Tracy

Letter 10 – Thread Legged Bug

Subject: Cute Little Mantis?
Location: Central Texas
October 21, 2013 6:38 pm
Hey Bugman!
Its been years since I have submitted a request. You may not remember me, but I shared a spider love story with you 2006, I think it was.
Anyways, here is a new little guy I cant identify . I think it is a type of mantis, but cant find a similar photo online. Help?
Details: 2033 on 21 Oct 2013.
Central Texas in heavy mesquite brush location. This was outside my cabin in a mowed yard. Typical yard critters are my bunnies, tarantulas, really fat orb weavers, tarantula hawks, fire ants, walking sticks, translucent pink gecko things, and cute little preying mantises.
Signature: Critter Lover

Hi Critter Lover,
Is this your posting of courting Jumping Spiders?  It is easy to confuse this Thread Legged Bug in the subfamily Emesinae with a mantid because they both have raptorial front legs used to capture and hold prey while feeding.  Mantids chew food while Thread Legged Bugs, like other Assassin Bugs, suck the fluids from the prey.

Letter 11 – Thread-Legged Bug

Subject: Is this a matisfly or a small mantis?
Location: Torrance, CA
January 23, 2014 3:50 pm
Hi there,
Every now & then, one of these will come into the house. They are tiny… about .25″ in body length and have very long, jointed antenna. I’ve watched them hunt and they first feel something their antennae, use the antenna to size up the potential prey’s size and then snag it with their catching arms.
I’d never heard of a mantisfly, until reading about them a few minutes ago. Is this critter in the picture a small species of mantis, mantisfly or something else?
I confirm that I am the owner of this photograph, although I have it posted on other sites, too.
Thank you for your time & expertise 🙂
Signature: Jeffrey

Hi Jeffrey,
This Thread Legged Bug is in the Assassin Bug subfamily Emesinae.  We have photographed a very different looking Thread-Legged Bug at our Mount Washington, Los Angeles porch light, and though we have not taken any new photographs, we do see them quite regularly.

Thank you for your very quick reply & identification, Daniel! 🙂
Take care!
Jeffrey

Letter 12 – Thread Legged Bug

Subject: Bouncing spider?
Location: 90066-2724 Mar Vista CA
May 24, 2016 10:38 pm
My brother noticed this bug on a chunk of wood from the wood pile. We thought it was a spider. He didn’t dart around at all, just mostly bounce up and down. What is it?
Signature: Bouncing Bug

This appears to be a Thread Legged Bug, one of the predatory Assassin Bugs in the subfamily Emesinae.  You can refer to BugGuide for additional images and information on this fascinating subfamily.

Letter 13 – Thread Legged Bug

Subject:  What is it?
Geographic location of the bug:  Mount Washington, Los Angeles, California
Date: 06/28/2019
Time: 08:09 AM PDT
Your letter to the bugman:  3legged.  Focus is a bit off. its foot closest us looks good.
How you want your letter signed:  Chris Howard

Hi Chris,
This is a Thread Legged Bug, an Assassin Bug in the subfamily Emesinae, and it is a beneficial predator.  It actually does have six legs if you look closely.  Four rear legs are used for walking, and projecting out in front of the two antennae are the pair of raptorial front legs that are used to capture prey.  Here is a BugGuide image for comparison.

Letter 14 – Thread-Legged Bug

Subject:  Bug walks on 4 legs with two grabber appendages
Geographic location of the bug:  Los Angeles, California USA
Date: 04/07/2021
Time: 12:56 PM EDT
Your letter to the bugman:  I found This tiny bug in my bathroom, it’s a bit longer than a small ant. I initially thought was a spider, but it appears to be an insect possibly as it has 6 appendages, it walks on 4 and has two grabbers like spraying mantis. What is it?
How you want your letter signed:  Thanks, David Holleman

Dear David,
This is an Assassin Bug in the subfamily Emesinae, the Thread Legged Bugs and there are several species on BugGuide listed in California, but the best we are able to provide with assurance is the subfamily identification.  BugGuide does support your observation by stating:  “Unlike walking-sticks and some dipterans they mimic, the Emesinae walk on the rear four legs — the front legs are modified for grasping prey.” Assassin Bugs are predators and some species are know to bite humans, so they should be handled with caution.

Letter 15 – Thread-Legged Bug from Canada

Subject: Thread Legged Bug?
Location: Coquitlam, BC, Canada
November 4, 2016 10:50 am
Hi,
I found this curious little guy in the mens washroom at my work in Coquitlam, British Columbia, in November. I had never seen anything like it, how it walked on 4 legs and carried its small front two similar to a mantis. A bit of research online, and I think I’ve narrowed it down to a thread-legged bug, but not sure of the species. Can’t find any reference to any in BC, and none of my books mention any thead-legged bugs.
Signature: Chris Doughty

Dear Chris,
We agree that this is a Thread-Legged Bug, one of the Assassin Bugs in the subfamily Emesinae, and our best guess is that it is in the genus Empicoris.  According to BugGuide the range is:  “much of the US and so. Canada; many spp. in Eurasia.”  Of the three species identified on BugGuide, only Empicoris rubromaculatus is reported in British Columbia.

Letter 16 – Thread Legged Bug eats Moth

Subject: Tiny praying mantis?
Location: Gilroy, CA, Watsonville Road near Uvas Creek: 37.02912ºN, -121.65475ºW
March 1, 2017 2:07 am
My grandson and I found this tiny bug dragging a moth across the screen of my tent. Although it looked like a praying mantis, it was so tiny that I wondered if it really was one. Could it be an instar? I I remember instars from Entomology at Cal Poly, but I couldn’t tell if it had wings. I released it after the photo shoot, but, alas, the moth was dead.
My grandson and I caught it October 3, 2010 around 5 pm and I have always wondered about it. I just ran across the pictures about the same time I received notification that there was a new comment about the Pacific Green Sphinx I submitted 1/17/2015, which reminded me to get in gear and find out about my tiny friend.
Signature: Bob

Dear Bob,
This is actually an Assassin Bug in the subfamily Emesinae, a group known as Thread Legged Bugs.  The moth appears to be a Geometer.  We are happy to hear the notice you received on the Pacific Green Sphinx triggered this new submission.

Hi Daniel,
Thanks for your super fast reply.  Wow!  An Assassin Bug?  I would not have ever guessed that!  The way it held its front legs made it look like a praying mantis to me, but I knew something was amiss because the rest of it looked more like a walking stick.
Thanks again.
Bob

Letter 17 – Thread Legged Bug from Los Angeles

Never Before Seen (By me!)
Location: Garden Grove, Ca
November 12, 2011 6:02 pm
Hi there. I found this guy one night on October 2, 2011 flying around my garage shop. NO idea what he is, but he is very cool looking. Released him safely to do his thang.
Thanks!
Signature: Greg M.

Hi Greg,
We believe we have correctly identified your Assassin Bug as a member of the genus Stenolemus based on this photo from BugGuide.

Letter 18 – Thread-Legged Bugs

Subject:  Never thought I’d see a predatory stick bug…
Geographic location of the bug:  Bergen, New York
Date: 08/07/2021
Time: 02:12 PM EDT
Your letter to the bugman:  Saw these guys on my tent. One actively eating a bug and the other just hanging out.
They are just short of two inches look.
How you want your letter signed:  KT

Dear KT,
These are Thread-Legged Bugs in the subfamily Emesinae, a subgroup of the predatory Assassin Bugs.  You can read more about Thread-Legged Bugs on BugGuide where it states:  “Unlike walking-sticks and some dipterans they mimic, the Emesinae walk on the rear four legs — the front legs are modified for grasping prey.”

Letter 19 – Unnecessary Carnage: Thread-Legged Bug in Mexico

Subject: sergio
Location: Culiacan, Sinaloa, Mexico
December 17, 2014 6:18 pm
hi i found this bug flying around my room, i killed it becouse i really never saw anything like this before, at fist i thought it was stick bug, but im not sure.
Signature: sergio

Dear Sergio,
This Thread-Legged Bug is a predatory Assassin Bug in the subfamily Emesinae, and though they might bite a human if carelessly handled, they are not considered dangerous.  Since they are predators, they are considered beneficial.  We hope you refrain from future Unnecessary Carnage now that you know this is not a harmful insect.  See BugGuide for additional information on Thread-Legged Bugs.