. Bulletin of the Department of Agriculture. Agriculture; Agriculture. 20 DEPARTMENT BULLETIN 1267, U. S. DEPT. OF AGRICULTURE A less obvious difference between the sexes is, as pointed out by- Casey, in the form of the pygidium, which is slightly shorter, more convex, and more broadly rounded at the apex in the male than in the female. The male claspers (fig. 11) are symmetrical, each consisting of a vertical flange resembling that of Ligyrus gibbosus (fig. 12) but considerably smaller and slenderer and with the upturned process on its postero-lateral face more nearly basal, toothlike, a
. Bulletin of the Department of Agriculture. Agriculture; Agriculture. 20 DEPARTMENT BULLETIN 1267, U. S. DEPT. OF AGRICULTURE A less obvious difference between the sexes is, as pointed out by- Casey, in the form of the pygidium, which is slightly shorter, more convex, and more broadly rounded at the apex in the male than in the female. The male claspers (fig. 11) are symmetrical, each consisting of a vertical flange resembling that of Ligyrus gibbosus (fig. 12) but considerably smaller and slenderer and with the upturned process on its postero-lateral face more nearly basal, toothlike, and extending obliquely backward. The female genitalia consist of two pairs of almost flat plates—a large superior and a small in- ferior pair, the latter fringed apically with short hairs. A pubic process is TIME OF EMERGENCE Fig. 9.—Ventral view of tip of abdomen of adult male Euetheola ruffioeps, showing1 structural char- acters. (Drawn by Henry Fox) The earliest date on which adults of the newly emerged generation have been ob- served under laboratory conditions at Tappahannock is August 13. This was in 1915, when an adult, reared from a larva collected June 30, appeared in one of the breeding boxes. The earliest date on which adults have been found in the field is August 24 (in 1915 and 1916). The period of emergence extends throughout the last part of August and the whole of September and October, although ordi- narily relatively few appear to emerge later than the end of Sep- tember. The latest emergence of which there is record is of two individuals which developed in the breeding boxes early in November. In 1915 the majority of the beetles emerged between September 1 and Septem- ber 25, the period between September 10 and Septem- ber 20 being especially pro- lific in emergences. COLOR CHANGES Fig. 10.—Ventral view of tip of abdomen of adult ITTU^-r, ^u^ ^A-,-,14-^ „™,«v.™« female Euetheola rugiceps, showing structural When the adUltS emerge chara
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