THE CANADIAN ENTOMOLOGIST 



plant, aided by the large muscles of their anterior and middle 

 femora. All sections of the leaf are attacked, specimens being 

 found close to the ground or far out at the tips of the leaves. The 

 sexes appear on the leaf very similar to the viviparous forms, with 

 the exception of the smaller size. The genus belongs to the Callip- 

 terini, but seems to be quite distinct from the other genera in the 

 tribe. 



It would appear that Theobald has been led into the error of 

 describing the cauda as bifid by the very marked division on the 

 last abdominal segment in the type species. In examining scirpus 

 this is the most apparent structure on the caudal portion of the 

 abdomen. The cauda, however, is distinctly knobbed, and the 

 anal plate in the apterous forms appears almost as two distinct 

 plates. This is more plainly seen in some of the other species than 

 in scirpus. 



The species may be separated by the following key: 



Key to Species. 

 (Based on Apterous Form.) 



1. Antennae not much longer than half the body length, and about 



equal in length to the distance between the vertex and the 

 hind coxse hallii (Gill.), 



Antennae much longer than the distance between the vertex 

 and the hind coxae, usually as long as the body 2 



2. Posterior extremity of the abdomen quite distinctly 



bilobed 3 



Posterior extremity of the abdomen not distinctly 



bilobed 4 



3. Body covered with fan-shaped or sickle-shaped hairs; vertex 



not strongly conical scirpus Theo. 



Body without hairs excepting simple ones on the caudal por- 

 tion; vertex strongly conical elongatus Baker. 



4. Body covered with fan-shaped hairs about 0.016 mm. 



long 5 



Body with slightly knobbed hairs about 0.05 mm. 



long americanus Baker 



