[Illustration: Fig. 3. Head of Caterpillar of Goat-moth (_Cossus_) seen from behind. _At_, feeler; _Mn_, mandible; _Mx_, maxilla; _Lm_, labium, spinneret projecting beyond it. Magnified. After Lyonet from Miall and Denny"s _Cockroach_.]

[Illustration: Fig. 21. Maggot of House-fly (_Musca domestica_), _a_, side-view, magnified 5 times; _b_, prothoracic spiracle; _c_, feeler; _d_, hind-region with posterior spiracles; _e_, _f_, head-region with mouth-hooks; _g_, head-region of young maggot; _h_, eggs. All magnified. After Howard, _Entom. Bull._ 4, _U.S. Dept. Agric._]