18 DEPARTMENT BULLETIN 1267, U. S. DEPT. OP AGRICULTURE 



DURATION OF THE PUPA STAGE 



The pupa stage may last from 9 to 44 days, but usually falls be- 

 tween 10 and 19 days, so that two weeks may be said to be a fair 

 average period for the duration of the stage under normal condi- 

 tions. The precise length of this period unquestionably is deter- 

 mined by the prevailing temperatures. Instances in which the length 

 of the stage is much in excess of the normal pertain to individuals 

 which have undergone their development late in the season. 



The earliest date on which pupse have been obtained at Tappahan- 

 nock is July 31, when there appeared in one of the breeding boxes a 

 pupa which had developed from a larva collected at the same locality 

 on June 30. The earliest record of actually finding pupse in the field 

 is August 12. They appear to be most abundant during the last part 

 of August and first half of September. Pupse have been found in 

 the field as late as November and it seems quite probable that a small 



Fig. 7. — Euetheola rugiceps: 

 Adult. (Drawn by Henry 

 Fox) 



Fig. 8. — Ventral view of adult 

 Euetheola rugiceps, showing 

 structural characters. (Drawn 

 by Henry Fox) 



number may fail to mature before winter. There is no evidence that 

 such pupse ever survive until the following spring, as all the pupse 

 in the possession of the writers buried in the ground at Charlottes- 

 ville perished during the winter. 



ADULT 



DESCRIPTION 



The adult of Euetheola rugiceps (PI. I, B; II, A; figs. 7, 8) is a rather stout, 

 jet black beetle, having an average length in Virginia and Tennessee material 

 of from 13 to 16 millimeters. The surface in recently emerged individuals is 

 highly polished, 6 but is dull and opaque in old and worn ones. 



5 Casey (1, p. 187) in his recent memoirs asserts that the body is " not very shining," 

 and gives this as one of the characters distinguishing Euetheola rugiceps from another 

 form from Honduras, which he describes as a new species, hondurana-. The writers axe 

 inclined to think from Casey's description that he had at hand only old individuals of 

 rugiceps — doubtless collected during the spring, as the younger ones, collected in the fall,, 

 are almost invariably rather highly polished and of an intense black color. 



