200 MOSQiriTOES OF NORTH AMERICA 



The type species are: of Deinocerites Theobald, Deinocerites cancer Theo- 

 bald; of Brachiomyia Theobald, Brachiomyia magna Theobald; of Deinoherides 

 Giles, Deinocerites cancer Theobald ; of Brachiosoma Theobald, no species in- 

 cluded; of Brachiosoma Blanchard, Deinocerites cancer Theobald. 



Genixic Diagnosis of Adult: 



Palpi short in both sexes, three-jointed, the last joint longest Antenns long and 

 Blender, similar in the sexes, the whorls of hairs at the bases of the joints short and 

 sparse, inconspicuous, the shaft with scattered hairs and coarse pubescence; second 

 joint about fourteen times as long as wide, or more; the third joint about two-thirds 

 the length of the second in the male, the succeeding joints successively shorter; in 

 the female the third joint is about one-third as long as the second, the succeeding 

 joints subequal. Prothoracic lobes remote dorsally. Mesonotum with longitudinal 

 rows of coarse setae. Postnotum nude. Abdomen compressed, truncate at the tip 

 in the female, the cerci stout, conical; abdomen of the male subcylindrical, somewhat 

 expanded at the tip, with stout claspers. Legs long and slender, the claws simple in 

 the female, toothed on some of the claws in the males of some of the species. 



Oenebic Diagnosis of Labta: 



Head large, transverse, rounded, ventral surface forming a lobe with a laterally 

 projecting angle to cover a process at base of mandible; antennae slender, with 

 small median hair-tuft Lateral comb present on the eighth abdominal segment 

 Air-tube elongate, with sparse basal pecten, followed by a single hair-tuft Anal 

 segment with dorsal plate and ventral brush; anal gills two, rudimentary. 



Littoral of the West Indian islands and Trinidad, southern Florida, both 

 Atlantic and Pacific coasts of Central America. The species are confined to the 

 crab-holes along the shore within reach of tide-water. 



The genus was at first involved in considerable confusion, the males and 

 females being described separately, two genera being erected on characters de- 

 rived from defects in the specimens, and the male of a species of Culex being at 

 first thought to be the male of Deinocerites. The matter was finally settled by 

 the receipt of sufficient good material. The name Brachiosoma, proposed by 

 Theobald, is without type, as no species were referred to it by its author. It is 

 treated by Blanchard as a synonym of Deinocerites, and is thus first validated. 

 It must be credited to Blanchard, with cancer as type and considered as a 

 synonym of Deinocerites. Mr. Theobald reduced the genera to one and Mr. 

 Coquillett united the supposed two species. The genus, together with its nearest 

 relatives, Dinomimetes and Dinanamesus, forms a very distinct group without 

 close relationships. It is, however, clearly not of subfamily rank, to which it 

 has been hastily assigned by three authors. 



The larvae inhabit crab-holes near the sea which are filled with bracMsh water. 

 The eggs and egg-laying habit are unknown. The larvse feed upon the matter 

 in suspension in the water, of which the excrement of the crab not improbably 

 forms an important part. The larva are in no sense parasitic on the crabs, as 

 stated by Wesche ( Joum. Eoy. Micros. Soc, 1904, 35) . The adults also frequent 

 the upper parts of the crab-holes above the water and do not wander far from 

 these situations. It is probable that they do not bite, at least not warm blooded 

 animals. 



Table of the Species, 

 adults, steucture and coloeation. 



1. Cerci of female large, conical, with two large terminal spines; claws of the 



male in part toothed 2 



Cerci of the female without terminal spines, hairy; claws of the male simple 



pseuies Dyar & Knab (p. 210) 



2. Cerci of female obliquely truncate, one spine below other; claws of male on 



front and mid tarsi with a basal tooth. . troglodytw Dyar & Knab (p. 206) 

 Cerci of female conical, both spines apical; teeth on claws of tarsi of male 



not basal 3 



