20 XOirril AMERICAN DIPTEHA. 



habits of only a few are knoAvn; one species, described by 

 Fritz Muller, from South America is said to be dimorpliic in 

 the 9, one form being sanguisugous, the other mellisugous. 

 The larvte live in running water. The head has a pair of slen- 

 der antennie ; the cephalothorax and the following segments, 

 each with a conical process bearing a bunch of bristles ; pupa 

 flattened, inactive and free, enclosed in a semioval, sliell-like 

 skin, the anterior end with horny erect breathing tubes. On 

 the under side the skin is soft and transparent, and provided 

 with three pairs of suckers by which the creature clings 

 most firmly. The flies are found dancing in the s})ray of 

 waterfalls, or resting upon the foliage near the margin of clear 

 running l)rooks. 



TABLE OF GENERA. 



1. An incompk'te longitudinal vein running into the posterior margin. 2 

 No incomplete vein running into the posterior margin ; proboscis much 



elongated; hind tibia^ with spurs; claws simple; eyes entire, not 

 bisected ($). (CeiUral and South America and West Indies.) 



r.M.TosrmiA Schiller. 



2. Second longitudinal vein furcate. .......•"> 



Second longitudinal vein not furcate. ...... 4 



•5. Origin of tlie anterior branch of the second vein coincident witii tiic 

 origin of the third vein; front tibia» curveil in $ . 



BiiiiocEi'ji.\LA <^ten Sacken. 



Origin of anterior branch of second vein niorc^ +14««il than the origin of 



the third vein ; front tibiai straight in the J. A(i.\Tiio\ Hoeder. 



4. Eves holoptic, bisected hy an unfaceted cross band or by a simple groove. 



Hi,i;pii.\i!()(i:uA .Mac(|uart. 

 Eyes broadly dichoptic and not bisected. . . LicoMorit.v Locw. 



4. CULICID.E. 



Slender flies, charcicterized by the ])r()jecting ])roboscis and 

 by the plumose antennte of the male. Head small, round ; 

 eyes reniform ; ocelli wanting. Antennae thread-like, com- 

 posed of fifteen joints; the first joint thick, the following 

 joints small, round, and beset with wliorls of hair, forming in 



