128 A Monograph of Culreidae. 
wing than that of the second posterior, its stem about half the 
length of the cell ; stem of the second posterior nearly as long as 
the cell ; posterior cross-vein about its own length distant from 
the mid cross-vein ; halteres with pale stem and black knob. 
Length.—3°8 to 4 mm. 
Time of capture-—December, in Trinidad (Urich). 
Habitat.—South America (Walker) ; Trinidad, at Aqua Santa 
(F. W. Urich). 
Observations.—The types of g and 9 in the British Museum 
are in very bad condition ; the @ has no legs nor abdomen, and 
the specimens are much faded. 
The specimens from which this description is drawn up are 
perfect. There is one small difference seen in the type, namely, 
that the posterior cross-vein is nearer to the mid than in the 
Trinidad specimens. The central thoracic scales are also bronzy, 
whilst in the specimens described here they are deep brown, but 
this is due to fading in the type. a 
Arribalzaga’s J. discrucians is larger, being 6 mm. His 
species has been sent over by Dr. Lutz, and was renamed by 
Colonel Giles J. Arribalzagae ; the type, a 9, is in the Museum. 
Giles is quite wrong in saying the true discrucians has an 
unadorned thorax ; the type shows it just as described here. 
JANTHINOSOMA LuUrzit. Theobald. 
(Mono, Culicid. I., p. 257, 1901.) 
Additional localities—Pomeroon Canal, Cara Cara Creek, 
Demerara River and Barima River, British Guiana (Dr. Low) ; 
Trinidad (F. W. Urich). 
Note.—The ungues of the fore and mid legs in the ? (vide 
Fig. 70, a) are strongly curved and uniserrated and can thus easily 
be told from J. discrucians (Walker). 
JANTHINOSOMA ARRIBALZAGAE. Guiles. 
Janthinosoma discrucians. Arribalzaga. 
(Culicidae, Giles, p. 341, 2nd ed.; Dipt. Argent., p. 53, Arribalzaga.) 
Head with orange scales, black at sides. Thorax black, with 
bronzy median and orange yellow lateral scales. Abdomen violet, 
with golden lateral patches ; venter violet, with narrow apical 
golden bands, base of abdomen yellow. Legs deep brown, with 
