NEMATOCERA: HARMLESS NEMATOCERA 129 



has a certain amount of resemblance to a Culicid larva, except that the 

 thorax is not differentiated from the abdomen : it consists of a head with 

 antenna, mandibles, and maxillse, and with mouth-brushes much like 

 those of a Cu/ex larva, and of 12 body-segments ; on the dorsal surface 

 of the penultimate segment of the body there is a pair of breathing- 

 openings like those of Anopheles situated in a depression which is 



^mouthhr. 

 T^ni breathing op. 



''.rang' 



'pseudop. 

 Fig. 34. — Larva of Df-ra. 



protected by stiff setose flaps ; on the ventral surface of some of the 

 body-segments there are pairs of spinose pseudopods. The larva creeps 

 about on aquatic vegetation close to the water's edge, and has the habit 

 of carrying its body strongly bent ; when submerged it swims by vigorous 

 contortions. The pupa much resembles that of Culicida. I have 

 received the larvas of Dixa as " worms " passed in the urine of a 

 patient — caveat medicaior. 



Family RHYPHIDiE. 



This is a very small family but is widely distributed. One of the 

 species, Rhyphus fenestralis (Fig. 35), is commonly found on windows 

 and mistaken for a mosquito, or even, by reason of its spotted wings, for 



Fig. 35. — Wing of miypliiis, 



an Anopheles. The antennae are of fair length, are composed of 16 

 segments, and do not carry whorls of hairs. In the wings there is a 

 discal cell, and the 2nd longitudinal vein is not forked. In the legs the 

 empodium is pulvillus-like, and the true pulvilli are vestigial. The larva 

 is slender and worm-like. 



Family CecidomyiD/E : Gall-gnats (Gr. Ki;Kis=a gall ; /tufa = fly). 



The species of this large family (Fig. 36) are small (often minute) 

 delicate midges, with long (often moniliform and plumose) antennae, long 

 slender legs, and broad, filmy, often hairy wings. The proboscis is 

 generally short. The wings commonly have only three longitudinal veins, 

 two of which are very faint ; but sometimes there are four or five ; the 

 costal vein is continued all round the edge of the wing. The tibias do 



I 



