THE BEETLES 



161 



bimaculatd} is a black beetle half an inch long, with yellow pro- 

 thorax bearing two black spots. Its larva mines raspberry and 

 blackberry canes. The red milkweed-beetles (Tetraopes tetra- 

 ophthalmus) are always common on the flowers of the milkweed, 

 and the larva bore in the roots and stems. 



III. BEETLES WITH THREE-JOINTED TARSI (TRIMERA] 



The ladybird-beetles (Cocdnellidae) form the only family of the 

 section Trimera, in which the tarsi have but three segments, and 



FIG. 235. The convergent ladybird-beetle (Hippodamia convergens) 

 a, adult ; l>, pupa ; c, larva. (After Chittenden) 



the head is usually concealed beneath the prothorax. Their small 

 size (few being over one fourth of an inch long), their broad, oval, or 

 hemispherical shape, 

 and their characteris- 

 tic markings, consist- 

 ing of "polka-dot" 

 black spots on a yellow 

 or red background, 

 or red or yellow spots 

 on black, make them 

 readily recognizable, 

 though now and then 

 certain of the leaf- 

 beetles, which have a 



general resemblance, 

 are mistaken for them . 

 Nearly all of this 



FIG. 236. The spotted ladybird-beetle (Megilla 

 maculata] 



a, larva ; b, pupa ; c, adult. (After Chittenden, United States 

 Department of Agriculture) 



