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



°E. quercipisi Fitch. 



Length 2.5-3 mm. ; mostly black ; anterior and middle femora 

 black or brown in the middle, their tibiae usually white, but often 

 brown in the middle, all tarsi white. 



^E. lanulas Fitch. 



Length 2 mm. ; mostly black ; only tarsi white, and these with 

 their tips dusky; abdomen smooth and poHshed. 



Bred from galls on willows and woolly galls on oak leaves. 



°E. querciglobuli Fitch. 



Length nearly 4 mm.; mostly black; basal joint of antennae 

 dull white; legs dull white, except the femora, which are pale 

 dull yellow; abdomen tinged with pale dull yellow beneath. 

 °E. auriceps Walsh. 



Female: length 2.5-3.5 ^^- Male: length 2.5-3 nim. ; hair 

 of head and rest of body golden yellow ; apical joint of antennae 

 sometimes rufous; hind coxae occasionally tinged with black ex- 

 ternally. Female with the hind coxae and occasionally with a 

 cloud in the middle of the anterior portion of hind femora, black, 

 or the hind femora entirely black in the middle, mid and front 

 coxze generally more or less black, abdomen in female entirely 

 black. 



Bred from Philonix erinacei.- 

 °E. dorcaschemae Ash mead. 



Female and male: size similar to that in bolteni and 

 studiosa; male hardly separable from these two species; legs, 

 except knees and tips of tibiae, black. 



Bred from Dorcaschema alternatum. 

 °E. sp. 



Host : Aulacidea solidaginis. 



Isosoma Walker. 

 To this genus belong the joint worms that are injurious to 

 grain, but can be kept in check by seeing to it that all straw of 

 any one season is entirely used up before the advent of another 

 spring. 



Key to Species. 



Fetnales. 



I. Mesonotum not smooth 2 



Mesonotum smooth and polished 4 



