THE DIPTERA. 
125 
cent. Such are the fire-flies^ the cucuyo of the West 
Indies, and the glow-worm. 
Fig. 159.— The early stages of the common House-fly. A, dorsal and B. side view 
of the larva; a, air-tubes; sp, spiracle. C, the spiracle enlarged. F, head of 
the same larva, enlarged; hi, labrum (?); md, mandibles; mx, maxillae; af, 
antennae. E, a terminal spiracle much enlarged. D, puparium; sp, spiracle. 
AJl the figures much enlarged. 
Order 13. Siphonajdera. — Fleas represent this group. 
Order 14. Diptera, — The common house-fly (Fig. 159) 
is a type of this group, all the members of which have but 
Fig. 160.— Bot-fly of the ox and its larva. 
two wings, while the tongue is especially developed for lap- 
ping up liquids, The common house-fly lives one day in 
