486 CONNECTICUT GEOL. AND NAT. HIST. SURVEY. [Bull. 



combined; prothorax about twice the length of the mesonotum, 

 polished, except the neck-like portion, which is finely rugose; 

 scutel smooth, with a transverse subapical impressed line, post- 

 scutel with a row of round punctures back of it, metathorax as 

 long as scutel, tricarinate, smooth and shining; legs mostly like 

 rest of body, posterior femora geneous, tarsi fuscous above, with 

 short dense pale pubescence beneath; wings hyaline, strongly 

 iridescent, veins black, marginal vein more than two-thirds the 

 length of the si:|JDmarginal, postmarginal and stigmal equal, about 

 three times as long as thick. 



Bred from the larva of the horn-fly (Hcematobia serrata). 

 ^S. sp. 



Parasite on dipterous larvae. 



TRIDYMIDiE. 

 Antennae inserted at the middle of the front, clypeus not pro- 

 duced, both ring- joints visible, or only one. 



Key to Genera. 



1. Notauli complete 2 



Notauli not complete Hemadas p. 487 



2. Wings ciliate at apex Semiotellus p. 486 



Wings not ciliate Systasis p. 486 



Semiotellus Westwood. 

 °S. suborbicularis Provancher. 



Female : length a little over 2 mm. ; metallic blackish brown 

 above ; scape yellowish black ; legs honey-yellow ; wings hyaline, 

 grayish, veins nearly colorless; abdomen depressed, polished, 

 nearly circular, with a small point at apex. 



Systasis Walker. 

 °S. diplosidis Eckel. 



Female : length 3.5 him. ; mostly metallic blue-green, with the 

 blue predominating ; head three times as wide as long, rather con- 

 fluently punctate, shagreened between the punctures, lateral 

 ocellus as far from the eyes as from the median ocellus ; antennae 

 black except at base, twice as long as the head is high, scape 

 yellow, one ring-joint present, joints of flagel equal in length 

 and gradually increasing in thickness, except the first, which is 



