Maybe moth cat - BugGuide.Net

Moved

Moved from ID Request. Seems that trying here might make some sense.

… John R. Maxwell, 24 October, 2009 - 6:39pm

A few thoughts

Was this a really long strand of silk it was hanging from? If so, I think that's a habit that's unique to lepidopteran larvae (apart from spiders, of course). This looks to be within the variation of leaf-mining moth larvae I've seen, but I'd be interested to hear what Terry Harrison would say about that. Meteorus braconids and some campoplegine ichneumonids hang from a thread before spinning a cocoon, but this isn't more than a few cm long. I can't think of any other hymenopterans that would do anything remotely similar. Among flies, the only possibilities I can think of are fungus gnats, which do spin silk but don't (as far as I know) look like this or hang from long strands, and gall midges, which sometimes spin silken cocoons but I think they just drop to the ground without a silk line. Maybe I'm wrong about that... if you see another, put it in a container and see what it turns into!

… Charley Eiseman, 20 September, 2009 - 11:57am

Not a lep

I am assuming that this larva did not have true legs, prolegs, or crochets. If so, then we can rule out Lepidoptera. Several different Lepidoptera families (e.g., Nepticulidae, Tischeriidae, Heliozelidae) feature internally-feeding larvae that have lost all of the aforementioned structures, but virtually all of these larvae are dorsoventrally flattened and are nowhere near 6mm in length when mature. About the only featureless internally-feeding lep larva that is as long and as stout as the larva in this photo would be one of the yucca moths (Prodoxidae), which of course would have no earthly business dangling from a tree limb on a 4-to-8-foot strand of silk; plus, at least in prodoxids that occur in the eastern USA, the larva has a typical, caterpillar-like head capsule (see here), rather than the very reduced head that is seen in the photos of the mystery larva.

The identity of the larva shown here resides either in Diptera or in Hymenoptera.

… Terry Harrison, 21 October, 2009 - 4:58pm

Length of strand

I would guess that it was many feet (4-8) long. It swayed quite far in the breeze, I couldn't tell which branch it was coming from, but I hooked at least 18in. with my hand and placed it on my ruler.

… John R. Maxwell, 20 September, 2009 - 12:24pm

Well...

If I ignore the silk thread, I guess I agree with Eric that it seems most reminiscent of a hymenopteran... not that my opinion is worth very much. There are certainly other parasitoid wasp larvae that have silk glands for cocoon-spinning, so maybe there are some that do this.

… Charley Eiseman, 20 September, 2009 - 8:52pm

We would leave them at ID Request

for a while longer and see if you get any nibbles from any of the experts??

… john and jane balaban, 20 September, 2009 - 11:17am

Frass?

Or place at some order hoping an expert can help? Either is fine with me. Obviously they have no value without more certainty.

… John R. Maxwell, 20 September, 2009 - 10:36am

Maybe

for the time being, place half the images in Hymenoptera (or parasitic Apocrita) and half in Diptera? I'd really like to find out what this is (or might be, in the opinions of specialists).

… Charley Eiseman, 22 October, 2009 - 4:05pm

We don't see any legs or prolegs.

Does that make this a fly?

… john and jane balaban, 14 September, 2009 - 4:34pm

Could also be a leaf or seed miner

Some leaf- or seed-mining moth larvae lack legs and prolegs. However I don't know if any of them have so poorly-defined a head capsule.

… Peter Edelman, 14 September, 2009 - 8:32pm

Parasite?

I wonder if this is an ichneumon or braconid larva that just exited a host caterpillar?

… Eric R. Eaton, 15 September, 2009 - 12:11pm

Funny

Moth, fly, wasp, I was hoping for maybe a moth superfamily and we can't tell order. Next I want a guess outside of Arthropods!!! Pretty fun though. :-)

… John R. Maxwell, 15 September, 2009 - 1:55pm

Maybe

I guess (if they can spin a strand of web) it could have been trying to get to the ground to pupate?

… John R. Maxwell, 14 September, 2009 - 4:41pm