182 NEW YORK STATE MUSEUM 



Imago. Rather large to very small species, characterized by the 

 structure of their antennae and the wing venation. Head small, 

 somewhat compressed laterally; epistome somewhat prominent, 

 and usually hairy; proboscis short; palpi incurved, four jointed, 

 the last joint somewhat elongated. Antennae of the male 14- 

 jointed, the first joint large, disk-like; the second cylindrical, 

 the following ones rounded and closely crowded, the last joint 

 very long, often as long as the others taken together; all long 

 plumose; that of the female 7-jointed, the first disk-like, the second 

 cylindrical, the following egg or pear-shaped, short verticillate, 

 the last one cylindrical or ellipsoidal, short-haired; eyes reniform, 

 ocelli are wanting. Mesothorax highly arched, projecting over 

 the head, without transverse suture, with a depressed area in 

 front of the scutellum ; the pectus deeply arched, scutellum small ; 

 metanotum well developed. Abdomen long and narrow, com- 

 pressed cylindrical, 8- jointed; hypopygium tong-like. Legs very 

 slender and long, especially the anterior pair, which are widely 

 separated from the following pairs; coxae elongated, the tibiae 

 sometimes very short, and the metatarsi often much elongated, 

 the vesture woolly and short, sometimes fringe-like; claws and 

 pulvilli present. Wings long and slender, hairy or bare, folded 

 over the abdomen when at rest; in the male often shorter than 

 the abdomen. Venation as in the figures on pis. 28, 29, 30, and 

 31; anal angle present; the halteres free. 



Van der Wulp (1874) divided this group into a number of genera, 

 using as characters for the subdivisions the relative length of 

 the fore tibia to the metatarsus, the condition of the wing, i. e., 

 whether hairy or bare, and the counse of the cubitus. Deiscrip- 

 tions of th'ese genera are given on subsequent pages. 



Genus 37. Thalassomyia Schiner 

 Verb. zool. bot Gesell. 6:218. 1856 



This genus wasi erected by Schiner (loc. cit.) to contain the 

 species T. f r a u e m f e 1 d i , of which only the female was 

 known. More recently Dr Tomosvary (1884) described another 

 species T. c on gregat al, and in 1903 the writer described 

 the male and female of a third, T. o b s c u r a . Ooquillett 

 (1902) described a fly which he called O r t h oi cl a d i u s 



