fly (which are much thinner than Gauromydas) is Holorusia brobdignagius. It can attain about the same head-and-body length and wingspan, but if the legs are extended in front of and behind the body, then an overall length of makes it the longest true fly. Booklice (Psocoptera) The largest of this order of very small insects is the barklouse of the genus Psocus, the top size of which is about . Fleas (Siphonaptera) The largest species of flea is Hystrichopsylla schefferi. This parasite, known exclusively from the fur of the mountain beaver, can reach a length of . Thrips (Thysanoptera) Members of the genus Phasmothrips are the largest thrips. The maximum size of these species is about . Caddisflies (Trichoptera) The largest of the small, moth-like caddisflies is Eubasilissa maclachlani. This species can range up to across the wings. Silverfishes and allies (Thysanura) These insects, known to feed on human household objects, are up to in length. One 350 million-year-old form grew up to long. Angel insects (Zoraptera) The largest angel insect species, Hubbard's angel insect (Zorotypus hubbardi), grows up to in length. References Largest insects Insects Insects