THE H0U8E-FLT. 



355 



in all directions. A few beetles are phosphorescent. Such 

 are the fire-flies, the cucuyo of the West Indies, the glow- 

 worm, and certain grubs, such as Asiraptor illuminator 

 (Pig. 340), Melanactes, and the young of a snapping beetle. 



Fig. 343.-Bot-fly of the ox and its larva. 



Order 13. Siplionaptera. — The fleas (Fig. 341) are wing- 

 less, with sucking moutli-parts; all the palpi fonr-jointed. 



Order 14. Diptera. — The common house fly (Pig. 342) is 

 a type of this division, all the members of which~have but 

 two wings, while the tongue is especially developed for lap- 

 ping up liquids. The common house- 

 fly lives one day in the egg state, from 

 five days to a week as a maggot, and 

 from five to seven days in the pupa 

 state. It breeds about stables. 



The Tachina-fly is beneficial to man, 

 from its parasitism in the bodies of 

 caterpillars and other injurious insects. 



The bot-fly (Pig. 343, Hypoderma 

 hovis DeGeer) is closely allied to the ^f^f- ^^^--Syrphm poiuus 

 house-fly, but the maggot is much 

 larger. The larval bot-fly of the horse lives in the stomach, 

 that of the sheep in the frontal sinus. 



The Syrphus flies (Fig. 344, Syrphus politus Say) mimic 

 they are most useful in devouring aphides, while in 



