440 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 9 



( 9 ) Not definitely known. 



Described from 11 male specimens, 71 others examined. 



Range. — New England: Mass.; Wellesley, Westfield, Melrose 

 Highlands, Harwich, Forest Hills, Lunenbm'g. 



United States: N. Y. 



Foreign: Canada (Quebec). 



This species is named in honor of Dr. J. M. Aldrich. 



The bristles are long and slender, except on the legs. It is peculiar 

 that the left sternopleura often bears two sternopleurals, the right one 

 three, while in none of the specimens examined was the reverse con- 

 dition found. The rows of cilia should be counted on that portion of 

 the back of the head which is nearest the epicephalon. In exposing 

 the genitalia the forceps are likely to be spread and flattened out so 

 that they do not appear normal. 



S. aldrichi is extremely similar to S. uliginosa Kramer. Though the 

 penes are distinctive, those external characters which have a differen- 

 tial value are somewhat \ariable. The most constant distinctive 

 character seems to be the presence of a row of long, scattered hairs on 

 the distal half of the lower posterior face of the hind tibia, while in 

 S. uliginosa the hairs are close set and form a distinct beard on the 

 distal three-fourths. The number of rows of black cilia behind the 

 eyes, commonly a reliable specific character, varies in both species. 

 In aldrichi there are usually but two rows of bristles on the anterior 

 femur, but sometimes an intermediate row is weakty developed; 

 uliginosa, on the other hand, commonly has three rows though oc- 

 casionally the intermediate one is so weak as to resemble that condition 

 in aldrichi. Uliginosa seems to constantly have three sternopleurals, 

 in aldrichi the number varies. In the former anterior acrostichal 

 bristles, except the presutural pair, are usually absent, while in idiginosa 

 all are commonly present; but again this character varies in both. 

 Though the penes are specific, the fourth ventral plates are alike, as 

 are also the forceps. 



S. aldrichi agrees with S. idiginosa Kramer, S. idilis Aldrich, *S. 

 sarracenice Riley, S. exuberans Pandelle, *S. harpax Pandelle and three 

 undescribed New England species in the absence of marginal bristles 

 on the first abdominal segment. These bristles are sometimes absent 

 in S. sinuata Meigen. It agrees with S. idiginosa Kramer, *S. sar- 

 racenia Riley, >S. exuberans Pandelle, S. harpax Pandelle, S. hwnior- 

 rhoidalis Meigen, S. dalmatina Schiner, ^S. falcidata Pandelle and one 

 undescribed species in the presence of a row of long, slender hairs on 

 each side of the connecting membrane just anterior to the humps of the 

 first genital segment. This is rather obscure, and interesting to show 



