THE MEGALORHININA 207 



forked scales, and never with flat scales ; palpi as long as the proboscis 

 in both sexes. Dorsal surface of thorax seldom densely clothed with 

 scales. Scutellum simple, not lobed. Abdomen clothed with hairs or 

 scales, the latter, if present, usually confined to the last segments, and 

 then often inconspicuous. Wings as a rule spotted. 



THE MEGALORHININA 



This group of mosquitoes, according to Theobald, contains three genera 

 Megarhinus, Robineau-Desvoidy, Ankylorhynchus, Lutz, and Toxorhyn- 

 chites, Theobald ; some of them are the most brilliantly coloured of all 

 the mosquitoes ; many of them have caudal tufts of hair-like scales on 

 each side of the abdomen. Their large size, bright colours, and long bent 

 proboscides are points which help in recognizing them. In Megarhinus 

 and Ankylorhynchus the palpi are long in both sexes ; in the former the 

 last palpal segment in the female is rounded off, while in the latter it is 

 round and pointed. In Toxorhynchites the palpi of the female are 

 short, about one-third the length of the proboscis. 



Theobald recognizes eleven species of Megarhinus, which are confined 

 to North and South America and the West Indies ; he states that the 

 species described from India and Ceylon probably belong to Toxorhyn- 

 chites. Peryassu and Bourroul have figured and described the larvae of 

 some of the Brazilian species ; they are all predaceous, and are found in 

 water-buts and in holes in trees, where they live entirely on other mos- 

 quito larvae. The anal fin is wanting, but the terminal segment has four 

 knob-like processes. The thorax is furnished with stout serrated spines 

 and the abdomen has dense lateral tufts ; the breathing syphon is rather 

 short and ends in a valve with four flaps ; the mandibles are very power- 

 ful. The whole larva is often blotched or streaked. The pupa has 

 curved breathing trumpets, and two well-developed caudal fins. The 

 eggs are elongated, pointed at one end and somewhat blunt at the other. 



There are four species of Ankylorhynchus from South America, one of 

 which has no caudal tufts at the end of the abdomen. 



Theobald describes twenty-three species of Toxorhynchites from various 

 parts of the world. T. immisericors is a common species in India, and 

 breeds in holes in trees, in tanks, water-buts and tubs in which water 

 is allowed to collect. The larvae are predaceous, though, in the case 

 of some of the species, they ,do not .feed on their own kind ; the eggs 

 are laid singly. 



