GNATS, MIDGES, AND MOSQUITOES 



245 



my skin with a pin, and rubbed the pricks with bruised 

 mosquitoes, and no swelling ensued." On the whole, 

 therefore, it must be admitted that great difficulties 

 beset both of the two hypotheses that have been com- 

 monly advocated in explanation of the swelling and 

 pain consequent on the bite. Of course similar remarks 

 would apply in the case of both bugs and fleas. 



There seem to be chiefly two species of true gnats 

 that infest houses in this country, which are named 

 Culex annulatus and ciliaris. 

 The former has pretty spotted 

 wings, but must not be con- 

 founded with another spotted- 

 winged gnat-like fly (Fig. 75), 

 which is frequently found in 

 windows, and is generally 

 called the "Window Gnat" 

 (Rliyplms fenestralis). The 

 specific name fenestralis (from 

 Latin fenestra, a window) was 

 given to it in consequence of 

 its usual habit of flitting 

 about windows. It belongs, 

 however, to a different family, 

 and its habits and life-history 

 are totally unlike those of the 

 true Culices. Its larva is 

 terrestrial, not aquatic, and 

 lives in dung. Culex ciliaris, specially known as the 

 "house gnat," is a reddish-brown insect, with greyish 

 wings. 



The Culices, or true gnats and mosquitoes, are not the 

 only "thread-horned" flies that trouble mankind by 

 sucking blood, though they are usually the chief ; it is 



FIG. 75. Window Gnat 

 (Rhyphus fenestralis). 



