CHUYSOMELA. 265 



Somewhat convex. Blue ; base of antennae yellow- 

 brown. Thorax finely punctured, sides separated by a 

 fold beliind. L. 2f — 3 1. Not uncommon. 



C. didymatay Scrib. 



Lima, 



A. Thorax without separate side border. 



Metallic-blue or green, rarely black; base of antennae 

 and margin of apex of abdomen reddish-yellow. Thorax 

 punctured finely and scantily on disc, more coarsely at 

 sides. L. 2| — 4 1. Moderately common. L. aenea, Fab. 



S, Thorax with separate side border. 



a. Side border of thorax feebly separate, rounded behind. 



Black blue ; elytra red, with a small black spot at apex. 

 Thorax coarsely punctured. L. 4| — 6 1. Common. 



L. populi, Lin. 



b. Side border of thorax strongly separate, sinuate 

 behind, with prominent posterior angles. 



Blue-green ; elytra red. Thorax coarsely punctured. 

 L. 3^ — 4:^ 1. Rather common. Z. longicollis, Suffr. 



Gonioctena, 



A. Body broad and flatly arched, interstices on elytra 

 closely punctured ; all tibiae distinctly spined. 



a. Head (except vertex) and legs red. 



Broad elliptic. Yellow-red ; vertex of head, two spots 

 at base of thorax, scutellum, five spots on each elytron and 

 under-side black. Elytra finely and closely punctured, 

 with distinct rows of larger punctures. L. 2J — 3^ 1. 

 Common. G. rufipes, Gyll. 



b. Head and at least part of legs black. 



I, Legs entirely black. 



Broad elliptic. Black ; thorax and elytra red, often 

 spotted with black or even entirely black; base of an- 

 tennae and apex of abdomen yellow-red. Elytra closely 

 and distinctly punctured, with rows of larger punctures, 

 almost effaced behind. L. 2| — 3^ 1. Common. 



G. viminalis, Lin. 



II» Femora and tarsi black, tibiae red. 



