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



beetles placed in the hibernating cages in the fall were living when 

 the cages were examined in the spring. That an equally heavy 

 mortality may obtain under natural conditions is indicated by the 

 fact that where the beetles had been quite abundant in the fall of 

 1915, only a few could be found in the following spring. Doubtless 

 if the species could be kept under constant observation. for a succes- 

 sion of years, it would be found that winter conditions constitute one 

 of the important factors controlling the destructive outbreaks of the 

 species which seem to occur at rather long intervals. 



APPEARANCE IN SPRING 



The beetles usually begin to emerge from their hibernating quar- 

 ters in the spring in late April or in early May, except in the most 

 southern portions of its range. The precise time of emergence is 

 governed by prevailing weather conditions. Comstock (3) states 

 that they become active as early as the middle of March in Louisiana. 

 At Tappahanock the earliest dates on which they have been seen 

 abroad were April 23 in 1915 and May 1 in 1916. At Clarksville, 

 Tenn., the junior writer first observed them at street lamps on April 

 18, 1917. McConnell recorded them (unpublished notes) as active 

 and destructive at Greenwood, Miss., on April 23, 1913. Webster 

 (IJt) reported them damaging corn in Louisiana on April 25, 1888. 

 Becker informed the junior writer that complaints of injury by the 

 beetles came in from southern Arkansas about May 1. 



Mating of Euetheola rugiceps is practically coextensive with the 

 period of its maximum activity. The earliest date on which the 

 beetles were observed in coitu was May 13, 1915, at Sharps, Va., 

 while the latest date on which they were observed mating under 

 natural conditions was June 20, 1915, at Tappahannock. In the 

 case of those kept in breeding cages, mating was observed much 

 later than this, one pair being observed in coitu as late as September 

 10. Mating normally takes place underground, though on one occa- 

 sion a pair were found in coitu on the surface in a slight hollow 

 at the base of a cornstalk ; they were also found mating in tin boxes 

 in which they were placed during collection. It seemed to be im- 

 material to the beetles whether soil was in the boxes or not. 



OVIPOSITION 



Oviposition was observed to occur at Tappahannock chiefly during 

 June, the earliest eggs being found on June 5. It would seem 

 probable that eggs may be deposited during July, but the writers 

 have no records of obtaining any during that month. Most of the 

 eggs are apparently deposited during the last half of June. Beetles 

 kept in cages under somewhat artificial conditions continued ovi- 

 position, except for temporary interruptions due to the inclement 

 weather, throughout the summer, and until as late as the last of 

 September ; a small number of eggs even being deposited in October 

 and in early November. In nature, however, such prolongation of 

 the breeding season evidently does not occur, as field experience 

 indicates beyond a reasonable doubt that practically all the beetles 



