120 American Midland Naturalist Monograph No. 3 



Genus Mansonia Blanchardi 



Mansonia Blanchard, 1901, C. R. Soc. de Biol., 53:1045. 



The genus Mansonia is represented in the United States by three species 

 belonging to two subgenera. Shortly after hatching, the larvae of Mansonia 

 attach themselves by means of the modified siphon, to roots or stems of plants 

 from which they obtain their air supply. The females are troublesome biters. 



salient characters. — Adults: The adults are difficult to separate from 

 other genera of Culicini. Palpi of male long, female palpi short. Male antenna 

 plumose. Postnotum without setae. Spiracular bristles absent; postspiraculars 

 present or absent. Pulvilli absent. Wings with many or all the scales broad. 

 Squama fringed. Male Terminalia: Variable in structure. Basal lobe either 

 appressed to basistyle or long and slender, usually bearing blunt spines or 

 modified filaments. Apical lobe absent. Dististyle variable in shape. Larva: 

 Two long filaments on antenna before tip. Anal segment long, completely 

 ringed by the dorsal plate. Comb of eighth segment of a few teeth in a single 

 row. Siphon short, without pecten. Siphon attenuated and modified to form a 

 saw-like apparatus for piercing underwater stems and roots of aquatic plants. 



Keys to the Species 



adult females 



I . Postspiracular bristles absent; segment 1 of hind tarsus with a pale ring near 



middle perlurbans (Walker), p. 127 



Postspiracular bristles present; segment 1 of hind tarsus without a pale ring near 



middle 2 



2. Palpus a little more than 1/3 as long as proboscis, with 4lh segment about twice 

 as long as 3rd; apical margin of 7th tergite bearing a close-set row of minute, 

 pointed spines (visible on pinned specimen with dissecting microscope) ; spines 

 of 8th tergite clumped posteriorly (visible only when softened in KOH and 

 dissected) Utillans (Walker) p. 124 



Palpus less than 1/3 as long as proboscis, with 4th segment about l|/2 times as 

 long as 3rd; apical margin of 7th tergite without minute spines; spines of 8th 

 tergite more or less uniformly spaced indubilans Dyar and Shannon, p. 121 



MALE TERMINALIA 



1. Dististyle without a tooth-like lateral branch on inner margin 



perlurbans (Walker), p. 127 



Dististyle with a tooth-like lateral branch on inner margin 2 



2. Dististyle not convoluted Utillans (Walker), p. 125 



Dististyle somewhat convoluted indubilans Dyar and Shannon, p. 121 



LARVAE (fourth INSTAr) 



1. Lateral spine of maxilla smooth; anal segment about twice as long as wide 



perlurbans (Walker), p. 128 



Lateral spine of maxilla strongly serrated on one side; anal segment about three 

 times as long as wide 2 



2. Comb scale long, slender, thorn-like, with a few minute spinules on basal portion 



titiUans (Walker) , p. 1 25 



Comb scale rather broad, fringed apically with several stout subequal spines 



indubilans Dyar and Shannon, p. 121 



1 See Edwards (1932) or Dyar (1928) for synonymy. 



