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 

 lacking. 



TIME OF EMERGENCE 



Fig. 9. — Ventral view of tip of abdomen of adult 

 male Euetheola ruffioeps, showing 1 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 characters. (Drawn by Henry Fox) 



from the pupa they differ 



greatly in color from the typical mature beetles. The earliest changes 

 in color take place during the closing days of pupal existence, while 

 the adult is still inclosed within the pupal integument. These 

 changes involve only the head and thorax, which at the time of 

 emergence are already well chitinized and bright orange red. The 

 elytra, however, at this time are quite soft and colorless, but assume 

 a pale creamy hue within an hour or two, also becoming perceptibly 

 firmer; in a few hours more this changes to a bright orange. The 

 following day, under normal conditions, the color of the elytra 

 gradually grows darker, becoming a vermilion red or Indian red. 

 In the meantime the head and thorax have been changing color 



