76 [April, 



unicolorous. Abdomen black and highly polished, 1st segment and base of 2nd 

 with a verj slight tomentum (causing a rather dull appearance) with a very faint 

 central stripe of polished black which is better seen from behind, 3rd segment with 

 an extremely narrow dull transverse band at base, 4th highly polished throughout. 

 Front femora with two small teeth ; a row of about six long postero-ventral 

 bristles in basal half. Middle tibiae with ttoo posterior bristles only, one of which 

 is median and the other at one-fourth to one-third from apex. Hind tibix with 

 one subapical dorsal, one median antero-dorsal, and one very tiny median postero- 

 dorsal bristle, a row of about six short and regular postero-ventral bristles in apical 

 half, and two to three much longer and more conspicuous antero-ventral bristles, 

 which are widely spaced so as to extend from middle to about one-fourth from 

 apex. Wings hyaline, veins (including costa) yellowish-brown, last section of 4th 

 longitudinal vein about three times as long as penultimate ; calyptra yellowish- 

 hyaline ; halteres black. Size, 3 — 3^ mm. 



Female : Not having seen an example of this sex I can only state that, 

 according to Stein the frons has a shining black middle stripe, the orbits are \\ke- 

 Vfise shining black, there is a distinct white spot over the base of the antennae; 

 thorax and abdomen shining black ; wings and calyptra yellowish. Judging from 

 the S , I assume that the middle tibiae are without anterior bristle, a character 

 which would at once separate this species from the next. 



The only specimens I have seen of this, the smallest of the 

 species of RydrotcBa, are three males taken by Mr. Verrall at New- 

 market on July 11th and 12th, 1901. It is abundantly distinct from 

 the next, although regarded as the same by the late Dr. Meade. 



18. — H. PAEVA, Meade. Male : Eyes bare, contiguous ; jowls very narrow as 

 in H. glabricula ; arist-a bare or nearly so. Thorax black, slightly shining and 

 with a faint olivaceous tinge ; shoulders distinctly cinereous. Abdomen shining 

 olivaceous, when seen from behind covered with a light bluish cinereous tomentum, 

 W!:ich leaves the base of the \st segment and a dorsal stripe on the remaining 

 segments black. Front femora with two small but distinct teeth, a complete row 

 of short and fine ventral hairs, among which stand three to four very long and 

 conspicuous bristles in basal half. Middle femora with two to three very long and 

 strong blunt ventral spines at one-fourth to one-third from base ; middle tibiae with 

 two posterior bristles, one of which is median and the other at one-fourth to one- 

 third from apex, and a single anterior bristle at one-fourth to one-third from apex. 

 Rind femora with two to three very long and fine postero-ventral bristles at about 

 one- fourth from apex ; hind tibiae viith a single subapical dorsal bristle, a single 

 small median antero-dorsal bristle, a single small median postero-dorsal bristle, 

 a very long, fine and characteristic posterior bristle a little before the middle, and 

 a row of four conspicuous antero-ventral bristles, which are widely and regularly 

 spaced so as to occupy all but the basal third or fourth, the one nearest the base 

 the longest, the others gradually smaller as they approach the apex. Wings usually 

 slightly tinged xvith yellowish-brown, last section of 4th longitudinal vein about 

 two and a half times as long as penultimate ; calyptra whitish-hyaline j halteres 

 black. Size, 3^ — 4 mm. 



