84 



In the jar in which they were placed, leaves of Chenopodium, Amaran- 

 thus and wild purslane (Portulaca oleracea) were placed, as these three 

 plants were known to be affected by insects of the genus and were at 

 hand for the purpose. The Chenopodium and Amaranthus were rejected, 

 but the larvae fed with avidity upon the Portulaca, and in due time 

 transformed to pupa and adult, the species proving to be Disonycha 

 caroliniana Fab.* 



By the 9th of August the largest larvae had attained full growth, 

 and on the following day had entered the earth. On the llth the 

 remainder had buried themselves in the sand with which their rearing 

 jar had been supplied. On the morning of August 17 all but one of 

 these larvae had transformed to the pupal condition. One imago fully 

 colored and one nearly so, were found on the morning of August 25, 

 having remained in the pupal condition about nine days. The remainder 

 passed the same time as pupae. The quiescent stage of the larva was 

 six days for the same temperature. The active stage was seventeen to 

 eighteen days, which gives about thirty-seven or thirty-eight days, a 

 figure that represents, in all probability, the minimum period, as the 

 weather averaged about 85° F. 



On a previous occasion, July 17, eggs were obtained, which hatched 

 July 22, or in five days. 



The egg did not present any character noticeably different from that 

 of xanthomelcena, which will be described in a forthcoming bulletin. 

 The larva and pupa, owing to their conspicuous coloration, were strik- 

 ingly distinct. 



The larva. — The larva when full grown is subcylindrical in form, 

 abdominal segments 2 to 7 subequal in width, the others gradually 

 narrowing toward the extremities. Ground color either olive or green, 

 variegated with red, forming with a dark-green medio-dorsal and two 

 submedial stripes, seven longitudinal stripes of alternate green and 

 red. Sometimes red and sometimes green is the prevailing tint. 

 Surface finely granulate, feebly shining. Aside from color the general 

 characters are much the same as in xantliomehcna, which has been 

 described in Bulletin No. 22, first series, p. 77. Each segment is pro- 

 duced into a transverse row of ten papilla?, each surmounted by a 

 small black piliferous wart, and terminating in a fine bristle. The 

 first thoracic segment has an additional row of papillae, and each spira- 

 cle is surrounded by a ring of black. Head small, nearly circular, 

 color shining black or very dark brown, triangular space in middle and 

 clypeus brown. The posterior end of the body .terminates in a prolog 

 which is concolorous with the surrounding portions of the terminal 

 segment. This is surrounded with two rows of black bristles, one 

 above and the other below. Legs considerably darker than the neigh- 

 boring portions; sutures and some other portions marked with black, 

 last joint nearly black. Length, 10 mm.; width, 3 mm. 



* Mr. F. M. Webster has recorded Portulaca as a food plant of this flea-beetle (Ent. 

 News, Vol. V., p. 41, May, 1894). 



