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A Monograph of Culicidae. 
Abdomen steely-black, covered with brilliant metallic blue 
and purple scales, becoming dusky towards its apex, with lateral 
apical golden patches to the segments, more or less triangular in 
form, the base of the triangles being parallel to the apical 
borders of the segments ; first segment dark, with dusky scales 
and long golden-brown hairs; venter purplish, with golden 
scaled apical cross-bands. 
Legs metallic purple in some lights, brown in others; coxae 
dark with yellow scales ; fore and mid femora yellowish at the 
base below, hind femora with a broad yellow ba.sal portion; knee 
spot pale; last two tarsi of the hind legs creamy-white, also the 
apex of the antepenultimate joint; ungues of the fore and mid 
legs uniserrated. 
Wings with a brownish tino-e ; veins clothed with brown 
scales, those at the base of the wing with purple reflections ; 
lateral scales long, rather broader than in Culex, apices convex ; 
first sub-marginal cell longer and narrower than the second 
posterior cell, its base nearer the base of the wing; its stem 
rather less than one-third the length of the cell, shorter than the 
stem of the second posterior cell, which is not quite as long as 
the cell; posterior cross-vein shorter than the mid cross-vein, not 
quite its own length distant from it. 
Halteres with pale stem and fuscous knob. 
Length .—4 to 5 mm. 
Habitat. — Itacoatiara, Lower Amazon (Austen); Rio de 
Janeiro (Lutz). 
Time of capture .—February (Amazon). 
Observations .—Specimens of this species have been received 
from Dr. Lutz and were named by him Janthinosoma discrucians, 
Wlk. I have compared them with the type in the British 
Museum and find they do not agree. It is clearly a new species, 
which can easily be told from Walker’s Culex discrucians by 
the last two hind tarsi and the apex of the antepenultimate 
one being white and by its larger size. In C. discrucians “ the 
base of the fourth joint is adorned with a pale yellow band,” 
and is so figured by Arribalzaga (Plate IV., fig. 6). C. dis¬ 
crucians is a Janthinosoma (vide Appendix). 
It might also be confused with J. musica, Say, but the 
honey-coloured head in that species and the non-ornamented 
thorax should at once separate them. From J. posticata it can 
be told by the last tarsal and apex of the penultimate one only 
being white in that species. 
