THE HOUSE-FLY. 355 
.all directions. A few beetles are phosphorescent. Such 
e the fire-flies, the cucuyo of the West Indies, the glow- 
orm, and certain grubs, such as Astraptor illuminator 
rig. 340), Melanactes, and the young of a snapping beetle. 
Fig. 343.—Bot-fly of the ox and its larva. 
Order 13. Siphonaptera.—The fleas (Fig. 341) are wing- 
38, with sucking mouth-parts; all the palpi four-jointed. 
Order 14. Diptera.—The common house fly (Fig. 342) is 
type of this division, all the members of which have but 
7o wings, while the tongue is especially developed for lap- 
ng up liquids. ‘The common house- 
’ lives one day in the egg state, from 
re days to a week as a maggot, and 
om five to seven days in the pupa 
ate. It breeds about stables. 
The Tachina-fly is beneficial to man, 
om its parasitism in the bodies of 
terpillars and other injurious insects. 
The bot-fly (Fig. 343, Hypoderma 
vis DeGeer) is closely allied to the gis %4—Suplus poliius 
use-fly, but the maggot is much 
rger. The larval bot-fly of the horse lives in the stomach, 
at of the sheep in the frontal sinus. 
The Syrphus flies (Fig. 344, Syrphus politus Say) mimic 
ips ; they are most useful in devouring aphides, while in 
