Description

Caddisfly larval case – Mollanidae sp.
Pliocene
Rita Blanca Formation
Oldham County, TX USA.
7mm caddisfly larval case on 46mm slab.

Insect.

The Mollandidae is a family of caddisflies which are not classified among true flies.  They belong to their own order, Trichoptera and are actually more closely related to butterflies and moths.

One remarkable fact about the group is that the aquatic larvae of some families build protective cases for themselves out of sand grains, gravel, wood bits, and other debris (all cemented by silk they produce).  These cases can be quite ornate and are also portable.  Another remarkable fact is that these larval cases have survived as fossils dating back to the Jurassic.  There is even a report of a case from a Permian-age site.