282 F. W. EDWARDS. 



Larvae. 



1 . Anal brush and barred area absent ; thorax with a strong spine at each 



posterior corner Rachionotomyia. 



Anal brush and barred area present (except in first stage) . . . . . . 2 



2. Siphon with one pair of ventral tufts . . . . . . . . . . . . 3 



Siphon with several ventral tufts . . . . . . . . . . . . 9 



3. Siphonal tuft at or near base . . . . . . . . . . . . . . 4 



Siphonal tuft near middle, or beyond . . . . . . . . . . 5 



4. Mouth-parts modified for predacity ; a chitinous plate on each side of 



eighth segment ; body colour dark reddish . . . . Megarhinus. 



Mouth-parts not modified for predacity ; a patch of scales on each side 

 of eighth segment ; body colour not reddish . . . . Theobaldia. 



5. Pecten teeth rounded and fringed apically ; a chitinous plate on each side 



of eighth segment (in fourth stage only) in addition to the comb 



Uranotaenia. 

 Pecten teeth (when present) sharply pointed, with denticles on one 

 side ; eighth segment with comb or patch of scales . . . . . . 6 



6. Valves of siphon and tracheal system highly modified for subaquatic 



respiration Tacniorhynchits. 



Valves of siphon and tracheal system not specially modified . . . . 7 



7. Extremely long single hairs on thorax and abdomen, besides long hair 



tufts ; dorsal chitinous plates on segments 6-8 in the fourth stage ; 



colour redcUsh Orthopodomyia. 



Single hairs not longer than the moderate tufts ; no dorsal chitinous 

 plates on segments 6-8 ; colour not reddish . . . . . . . . 8 



8. Pecten present Aedes. 



Pecten absent Armigeres. 



9. Mouth-parts modified for predacity ; anal segment long and pointed Ltdzia. 

 Mouth-parts not modified ; anal segment shorter and less pointed . . Culex. 



Genus Uranotaenia, Arrib. 



Most writers have distinguished this genus mainly by the short upper fork-cell 

 (cell Ro), but while this is a sufficient distinction in the majority of cases, there are a 

 few species [e.g.. U. iinguiculata) in which the shortening of this cell is not very 

 noticeable, and, on the other hand, some species of the Aedes group have the cell 

 so short that they have been mistaken for species of Uranotaenia. A more absolutely 

 diagnostic character, though requiring a high magnification for its detection, is the 

 absence in all known species of the genus of microtrichia on the wing-membrane. 

 This distinguishes Uranotaenia sharply from all other Culicidae. The short anal 

 vein, ending below or before the base of the radial sector, is shown also by the tropical 

 genera Hodgesia and Harpagomyia. In all known species except (/. unguiadata 

 the front claws of the male are small and equal in length. The pleural bristles are 

 very much reduced in number, there being only one or two in each of the pronotal, 

 pro-epimeral, spiracular and pre-alar series. 



The larva is not very sharply distinguished from that of Aedes, except in the 

 fourth stage, when the characteristic lateral chitinous plates appear on the eighth 

 abdominal segment. The spine-like frontal hairs found in many species are repre- 

 sented by normal simple hairs in others [e.g., U. imguiciilata) . The form of the 

 pecten-teeth is characteristic. The resting position in the water is almost horizontal. 



The genus is tropicopolitan, but two species occur within the limits of the Palaearctic 

 reejion. 



