Genus Janthinosoma. 
253 
Genus 5.— JANTHINOSOMA. Arribalzaga. 
(Dipt. Argentina, p. 52, 1891.) 
The following species, J. musica, Say, J. poslicata, Wiede¬ 
mann, and J. Lutzii, mihi, present such a marked different, 
appearance to other Culicidae that I propose to retain them in 
Arribalzaga’s genus. The head is covered with flat, rather broad, 
spindle-shaped scales and upright forked ones ; the thorax with 
short, brbad, spindle-shaped scales and also the scutellum ; the 
palpi densely scaly, and the third long vein is carried on through 
the basal cell as a bare pseudo-vein ; the ungues of the female 
are thick, serrated, and nearly equal ; in the male those of the 
fore and mid feet are unequal, the larger one with two teeth, 
the smaller with one ; on the larger claw the basal tooth is 
small and the long one blunt, on the smaller the tooth is basal. 
The hind legs are densely scaled and give the insect a 
characteristic appearance. In colour the abdomen is more or 
less purple and golden or pale scaled beneath ; male palpi long, 
longer than the proboscis by the two last joints. 
Although there is no very marked structural difference 
between these three species and Culex, there are sufficient minor 
details which, taken together with their markedly different 
appearance, will separate them at a glance from that genus. 
Walker’s C. discrucians falls in this genus also. 
1. Janthinosoma posticata. Wiedemann. 
Culex posticatus. Wiedemann. 
(Auss. Zwei. Ins. p. 9, et Dipt. Exot. i. 43, 2, Wied.) 
(Fig. 45, PI. XII.) 
Thorax brown, rather testaceous behind, with Hat, spindle- 
shaped, bronzy and yellow scales. Abdomen steel-black with 
metallic violet scales, with basal triangular patches of creamy 
scales ; venter yellow scaled. Legs dark brown with metallic 
steely and purple reflections, the last hind tarsal joint dull 
white, legs densely scaly. Wings with a brownish tinge. 
9 • Head steely-black, with dense, golden, forked upright 
scales behind, a few flat rather broad, creamy ones in front and 
a few purplish and then creamy ones at the sides; eyes pale 
steel colour and black ; bristles in front of the head black, two 
golden ones between the eyes ; antennae brown with the basal 
