THE ROTTGH-HEADED CORN STALK-BEETLE 



21 



rapidly and have become considerably darker than the elytra and 

 are a deep purplish" red. The elytra soon acquire the same shade. 

 The final stage naturally is the transformation of this color into 

 the deep black of the typical beetle. 



Under favorable conditions these color changes are completed in 

 from four to five days, but in cooler weather the time required to 

 effect them may be greatly extended. Thus, in October and Novem- 

 ber, beetles were frequently found to retain their 

 red coloration for a period of two or three weeks. 



ACTIVITY IN THE FALL 



Pig. 11. — Lateral 

 view of male clas- 

 per of Eiietheola 

 rugioeps. (Drawn 

 by Henry Fox) 



The adults appear to be much less active in the 

 fall than in the spring. So far as the writers are 

 aware, there are no records of the beetles having 

 been taken at lights during this season. At Tap- 

 pahannock, in the fall . of 1915, they were fre- 

 quently observed on or immediately under the sur- 

 face in the places where they had emerged. Al- 

 most invariably they were to be found beneath 

 clumps of their favorite food plants, Paspalum 

 spp., boring into and cutting off the culms of these grasses. The 

 junior writer never observed any of the beetles outside of their 

 natural habitat at this time of the year, but W. T. Emery, who vis- 

 ited the breeding grounds of the species at Tappahannock in early 

 November of 1916, reported that he had seen a small number crawl- 

 ing on an adjoining highway. Mr. Emery states that the day on 

 which these beetles were observed was unusually warm and mild, 



a circumstance which doubtless accounts for 



their wandering abroad. 



HIBERNATION 



Fig. 



No systematic observations on the hiberna- 

 tion of the beetles were made. So far as the 

 available evidence goes, it indicates that 

 hibernation takes place in the normal feed- 

 ing ground of the species and in much the 

 same manner as in other scarabaeids which 

 pass the winter in the adult stage. On one 

 occasion during the plowing of a timothy 

 pasture at Tappahannock in February of 

 terai view of 1916, the junior writer picked up a few 

 male ciasper of Uyyrun beetles of this species. The depth at which 

 Henry^Fox/ ' a w n by they occurred could not have exceeded 8 

 inches and was probably less 1 . From the 

 fact that some larvae reach maturity in cultivated fields, it is probable 

 that many hibernate there, but they are insignificant in comparison 

 with the much greater numbers that hibernate and emerge in the 

 normal habitat of the species. 



Experience with beetles kept in cages outdoors, during the winter 

 of 1915-16, indicates a heavy mortality among the hibernating 

 beetles during this season in the latitude of Virginia. At both 

 Charlottesville and Tappahannock only about a third of all the 



