190 MEDICAL ENTOMOLOGY 



thickened posteriorly in the male. Legs long and very delicate ; tibiae 

 without terminal spurs. Wings well developed ; the subcostal vein ends 

 about the middle of the wing; the second longitudinal arises from 

 the first, also about the middle of the wing, and appears to be the 

 commencement of the third vein ; it then arches forwards, and divides 

 into two ; the fourth longitudinal vein is also forked. The seventh vein 

 is rudimentary. There are four posterior cells, but the discal cell is absent. 



This group, the members of which are confined to the single genus 

 Dixa, Meigen, can be recognized by their large wings, distinct and 

 characteristic culicine-like venation, and their long filiform, almost bare 

 antennae. They are usually treated as a family, and are regarded as 

 being intermediate between the Tipulidae and the Culicidae. The char- 

 acter of the venation, the presence of the basal globular joint to the 

 antenna, the larger size of the claws of the fore and mid-legs in the 

 male, and their serration, are all points which link the Dixinae with the 

 Culicinae. 



The larva of Dixa was studied by Reamur in 1714, and later by 

 de Geer and Meinert, the latter depicting its structure in detail, as well 

 as that of the pupa. The larva consists of twelve 

 segments, and is bent at the fifth and sixth in the 

 shape of a syphon, so that the head and anal end almost meet ; in this 

 characteristic attitude it rests at the surface of water. On the ventral 

 surfaces of the fourth and fifth segments there is a pair of pseudopods 

 armed with hooks, and on the eighth, ninth and tenth there are a num- 

 ber of stiff spines grouped together. There is a respiratory cup on the 

 last segment, a terminal spine with three bristles, and two lateral 

 processes armed with long or short hairs ; in some species the fifth to the 

 tenth segments inclusive are furnished with shields bearing spines. 

 The larva is found in shady pools containing weeds and algae, and 

 as it is often of a dark brown colour, it may be easily overlooked. The 

 pupa, which is almost black, lies motionless at the surface of water with its 

 abdomen bent up under its thorax. It has a pair of respiratory trum- 

 pets just behind the head. 



Four species of Dixa have been described by Brunetti as occurring in 

 the Himalayas ; Adie records a species from Lahore. 



SUBFAMILY CORET'HRINAE 



Slender Nematocera with densely hairy bodies. Eyes kidney-shaped 

 and dichoptic ; ocelli wanting. Antennae long, markedly plumose in the 



