42 STUDIES IN NORTH AMERICAN MEMBRACID^E 



character and the two genera run into one another by almost 

 insensible gradations, the approach in our fauna being through 

 Ceresa femorata and Stictocephala festina var. angnlata. Canon 

 Fowler in the Biologia does not trust to the form of the pron- 

 otum but claims to have found other characters in the form of 

 the male genitalia that are sufficient. I have however been 

 unable to detect any such characters as he mentions without 

 dissection of the insect, which generally is out of the question, 

 and prefer to distinguish the genus on the form of the pronotum 

 which I consider amply sufficient. It has as good a standing on 

 this character alone as has such genera as Publilia, Glossonotus 

 and Telamona. All our described species are nearly or quite 

 unicolorous green in life with pronotum closely punctured, 

 The best characters with which to distinguish the species are 

 found in the form of the pronotum, face and last ventral seg- 

 ment of the female. The following key may assist in placing 

 our species; 



Carinate sides of the metopidium meeting before the middle of 

 the body, i. 



Carinate sides of the metopidium meeting at or behind the 

 middle, 4. 



1. Metopidium viewed from before obviously widened upward 



to the rounded suprahumeral angles; length 7^ to 



8 mm, 2. 



Metopidium not widened upward, frequently narrowed 



from the base, 3. 



2. Lorae continuing the rounded contour of the cheeks, the 



clypeus scarcely longer; last ventral segment of female 

 broadly subangularly excavated behind. Inhabits east 

 of the continental divide, 1, inermis Fabr. 



Lorae narrow, abruptly projecting beyond the nearly 

 straight apical margin of the cheeks ; clypeus much sur- 

 passing the lorae ; margin of the last ventral segment of 

 female oblique either side of the abrupt, deep median 

 notch. Inhabits California, 2, pacifica VanD. 



3. Metopidium convex, its sides vertical for a space, the 



carinate edges superiorly well arcuated; head rounded 

 before, the clypeus scarcely exceeding the cheeks ; length 

 7 mm. 4, substriata Walk. 



