212 PROCEEDINGS OF THE ACADEMY OF 



Our species can be arranged in four natural groups, of which the fourth 

 seems to be equivalent to the European genus Rhapidopalpus Iiosenh. 



A. Thorax without distinct impression, third" joint of 



antennae longer than the second. (Group 1.) 



Elytra yellow, with three broad hands and apex 



black 1. tricincta. 



Elytra with two transverse bands, and two poste- 

 rior spots on each, brown 2. connexa. 



B. The third joint of antenna? equal to the second : 



a. Elytra not striate ; thorax with two faint impres- 



sions. (Group 2.) 

 Elytra with twelve large black spots 



Abdomen and base of thighs yellow 3. 12-p u n c t a t a. 



Abdomen and legs entirely black 4. sorer. 



Elytra with twelve small black spots 5. ten el la. 



Elytra with transverse pale green bands 6. balteata. 



b. Thorax with two very deep impressions : 



*Elytra deeply striate. (Group 3.) 

 Elytra pale, with suture and submarginal vitta 

 black : 



Knees and tarsi black 7. vittata. 



Legs black, femora pale at tho base 8. trivittata. 



**Elytra carinate'towards the sides. (Group 4.) 

 Greenish yellow, elytra strongly punctured and 



subsulcate 9. longicornis. 



Black, elytra sparsely punctulate, prothorax yel- 

 low or black 10. atripennis. 



1. D. tricincta Lee, Say's Ent. ii. 222. GaHerucq trie. Say, Journ. 

 Acad. Nat. Sc. Phil. iii. 457; ed. Lee. ii. 221. 



Abundant along the Arkansas river, near the mountains : a specimen was 

 sent me from Arizona, by Dr. B. J. D. Irwin, TJ. S. A. 



2. D. connexa, rufo-fiava, nitida, capite fusco, elytris postice latioribus, 

 convexis, basi, fascia transversa ad medium, guttisqueutrinque posticis duabus 

 rufo-fuscis, fascia basali et mediali vitta angusta convexis ; postpectore tibiis 

 tarsisque obscuris, antennis fuscis basi pallidis. Long. "28. 



One specimen from Rio Grande, Texas. Of the same size and form as D. 

 12-punctata, but differing by the elongated third antennal joint, and by 

 the elytral markings, which are thus arranged ; a basal band extending from 

 the suture to the refiexed margin, another at the middle slightly oblique, 

 connected with the first by a short longitudinal stripe near the side ; two 

 rounded spots behind the middle, placed transversely, the outer one being 

 smaller and a little posterior. The thorax is quadrate, a little longer than its 

 width, smooth, and without impressions. The antenna? are fuscous, with the 

 first three joints pale ; the second is only one-third the length of the third, 

 which is as long as the 4th. The thighs are yellow, the tibia? and tarsi 

 fusceus ; the postpectus piceous. The scutellum is of the color of the 

 elytral bands. 



3. D. 12-punctata Dej., Cat. 405; Mannh. Bull. Mosc, 1843, 309. 

 Chrysomela, Gallcruca et Crioceris 12-punct. Fabr. ; Galleruca \2-punct. Oliv. 

 Ent. vi. 628 (No. 93, 23), pi. 2, f. 31. 



Abundant throughout the Atlantic district from Canada to Mexico ; vari- 

 eties sometimes occur, having the spots more or less confluent longitudinally. 

 The first three joints of the antenna? are yellow, the abdomen and base of the 

 thighs are also yellow. 



4. D. s or or. Diab'otica 12-punctata, var., Mannh. Bull. Mosc, 1843, 309. 



[Oct. 



