THe HyMENOPTERA OF MINNESOTA 185 
TEDTRASTIGCRIDAL 
Sub-marginal vein with from one to five bristles; post-marginal vein usually 
absent. Scutel with four bristles, all behind the middle; abdomen sessile; hind tibiae 
with one spur; male antennae simple. 
Fig. 67. Tetrastichus sp., bred 
from clover heads. 
Tetrastichus esurus Riley, is a parasite of the cotton worm. Many 
specimens have been bred from oak galls, and the genus Tetrastichus 
is a well-known parasite of the Hessian fly. T. racemariae Ashm., 
occurs in Minnesota. 
ENTEDONTIDAE 
Sub-marginal vein either ornate or provided with two bristles; scutel with two 
bristles near the middle. Hind tibiae and male antennae as in Tetrastichidae. 
An interesting family of parasites, its members attacking the 
mourning cloak butterfly, the peach lecanium, the white-marked tus- 
sock moth, and other injurious insects. The greater number of species 
appear to have been bred from leaf miners and particularly from the 
trumpet leaf miner of the apple, Tischeria malif oliella. 
In Minnesota, Mr. Marcovitch has reared Secodella argyrestheae 
Crawford from Argyresthia alternatella; also Achrysocharisk ansensis 
Gir. from eggs of the purslane sawfly. 
