ORTHOCH I LE — SY E 1 STROMA. 115 



ble microscopic pubescence. The inferior corner of the eye dis- 

 tinctly bordered by the narrow cheeks. Hypopygium entirely dis- 

 engaged, sessile, its exterior appendages lamelliform. The first 

 joint of the hind tarsi without bristles. The last segment of the 

 fourth longitudinal vein converges towards the third, although but 

 gradually, still sufficiently so as to reach the margin of the wing 

 quite far from its tip, in the immediate vicinity of the tip of the third 

 longitudinal vein. The whole structure of the body approaches 

 rather closely that of the species of Hereostomus, still the species 

 of Orthochile distinguish themselves sufficiently by the extraordi- 

 nary elongation of the proboscis and of the palpi, and by the pre- 

 sence of narrow cheeks ; besides, the tips of the third and fourth 

 longitudinal veins lie more closely together and farther from the 

 tip of the wing, than it is the case with any of the species of 

 Hercostomus. The described species of this genus are found in 

 Europe and in Asia Minor. The North American species, which 

 Mr. Walker described as Orthochile derempta, cannot, by any 

 means, be an Orthochile, as its arista has an apical position. In 

 what genus it is to be located, or whether a new genus is to be 

 created.for it, cannot be determined from the very imperfect state- 

 ments of Mr. Walker, as he does not even state the sex of his spe- 

 cimen, nor whether the first joint of the antennae is bare or hairy, 

 whether the first joint of the hind tarsi is bristly or without bris- 

 tles, and whether the fourth longitudinal vein converges towards 

 the third or not. 



The name of the genus (from 6p^oj, straight, and ^ao?, the lip) 

 has reference to the form of the proboscis, by which the species of 

 this genus can easily be distinguished. 



Gen. VIII. S1BISTROMA. 



The following are the most important characters of the genus 

 Sybistroma : Face not reaching as far as the lower corner of the 

 eye, very narrow in the male, very broad in the female. The first 

 joint of the antennae distinctly hairy on the upper side ; the second, 

 joint of the antennae transverse ; the third narrow and somewhat 

 long in the male, broad and short in the female. Arista sub- 

 apical-; in the male it is very long, its first joint longer than the 

 second and thickened at the end in the shape of a knot ; the second 

 has at its end a lamelliform enlargement. Scutellum very dis- 



