NOTES ON THE DIFFERENT GENERA 429 



Theobaldinella annulata, Meigen. 



This large gnat (6 mm. long) can be told by its wings having five large 

 spots of dark scales and by its legs having broad basal white bands to 

 the tarsi. The larvae occur in rain barrels and small pools. It is essen- 

 tially a domestic form, occurring in houses and privies. Its distribution is 

 Europe generally and North America. The bite is very severe, and in some 

 districts gives rise to painful oedema. 1 



Theobaldia spothipalpis, Rondani, occurs in Italy, Mediterranean Islands, 

 Palestine, the Himalayas, Khartoum, and in South Africa. It is about the 

 same size as T. annulata, but is yellowish-brown in colour, with striped- thorax 

 and mottled and banded legs. It occurs in privies and bites very severely. 



Genus Culex, Linnaeus. 



This large genus still contains many forms which should be excluded. 

 The species normally have narrow-curved median head-scales, and similar 



FIG. 277. WING OF A Culex. 



ones on the scutellum ; the $ palpi are shorter than in the former genus 

 and the male palpi are pointed ; the lateral vein-scales are narrow and linear. 



The type is Culex pipiens, Linn., the common gnat of Europe. The 

 thorax is covered with narrow-curved golden-brown scales, the abdomen 

 has basal pale bands to the segments and the legs and proboscis are 

 unbanded. The stem of the first submarginal cell is always less than one- 

 fifth the length of the cell. It lays its eggs in rafts, in water butts, &c., 

 and even in the foulest water. They are first deposited in England in 

 June and July and again soon after hatching in August. In some districts 

 this gnat bites man viciously, in others not at all. 



The common tropical gnat (Culex fatigans, Wied). This resembles the 

 European Culex pipiens, but can always be told by the stem of the first 

 submarginal cell always being much longer than it is in C. pipiens. This 

 is one of the species that has been proved to transmit Filariae to man, &c. 

 Varieties of it occur in almost every country between 40 N. and S., having 

 a very similar range to 5. fasciaia. In all countries it appears to be con- 

 nected with the transmission of Filariasis, 



Genus Melanoconion, Theobald. 



Mono. Culicid., iii., p. 238, 1903. 



This genus is composed of eight species, most of which are small black gnats 

 which bite viciously and which occur in swamps and jungles. They can at 

 once be told from Culex by the veins of the wings having dense broadened 



1 Second Report on Economic Zoology, p. 9, 1903. Theobald. 



