202 GEO. H. HORN, M. D. 



8. — Body beneath and legs eutii-ely black; thorax with three spots iu triangle; 



elytra punctate 12. triangularis. 



Body beneath and legs in part at least yellow 9. 



9. — Posterior femora entirely or in part piceous. 

 Body beneath entirely yellow. 



Head entirely yellow ; antennse with four basal and one or two terminal 

 joints yellow, femora (except posterior at apex) yellow ; tibia? and 



tarsi bla<5k ; elytra bright violaceous blue 15. varieoriiis. 



Head piceous; anteini» piceous; legs entirely black ; elytra blue-black. 



rather dull 14. cervicalis. 



Abdomen alone entirely yellow, hind femora bicolored. or entirely black ; 



head piceous; elytra blue-black 13. xaiitlioiiielaMia. 



Abdomen piceous at middle, apex and sides yellow, legs bicolored ; head 



bicolored; elytra brilliant blue 16. politiiia. 



Posterior femora entirely yellow ; abdomen piceous, apex and sides yellow ; 

 head bicolored. 

 Elytra blue or violet, form of body oval, as in xanthomelsena. 



17. iiiellicollis. 

 Elytra bright green, form more oblong 18. collata. 



1. I>. penusylvanica lUig.— Oblong, nearly parallel. Anteuuse a little 

 longer than half the body, moderately stout, black, except usually the under- 

 side of three basal joints. Head black, front yellow, surface nearly smooth, ex- 

 cept a small group of punctures near each eye. Labrum piceous or brown. 

 Thorax more than twice as wide as long, slightly narrower in front, disc convex, 

 somewhat uneven, a very indistinct, oblique impression beginning at the front 

 angles extending toward the middle, behind which is a more or less developed 

 umbone; lateral margin rather wide, the submarginal impression deep, surface 

 shining nearly smooth, the punctures very fine and indistinct ; color pale yellow, 

 with black spots varying in size and number. Scutellum black. Elytra yellow, 

 or yellowish white, with the suture, a marginal vitta (these rarely joining at 

 apex) and a median vitta not reaching the apex, black; surface subsulcate, espe- 

 cially near the sides, punctuation variable, either quite distinct or entirely obso- 

 lete. Body beneath nearly entirely black, side margin of elytra and outer side 

 of epipleurae yellow, the inner margin usually piceous. Abdomen densely punc- 

 tured and finely pubescent. Legs variable in color from black to rufescent. 

 Length .26— .30 inch. ; 6.5—7.5 mm. 



As might be expected in a species of such wide distribution, there 

 is considerable variation, the types of which will be considered sepa- 

 rately. 



Limbicollis Lee. — Antenn?e entirely black. Thorax with the spots 

 confluent in a large discal black space having a comparatively nar- 

 row yellow border. Thoi-ax beneath black, narrowly margined with 

 yellow. Body beneath and legs black. 



Fennsylvanica Illig. — Head in part yellow. Prothorax reddish 

 yellow, with a central black spot, round in front and gradually nar- 

 rowed posteriorly, beneath entirely yellow. Body beneath black. 



