THE GRAIN BUG. 



25 



Table VIII. 



-Daily activity and feeding TiaMts of adults of Cldorochroa sayi, 

 July 15, 1916 — Continued. 



Hour. 



Wire cage 3 by 3 by 3 feet over -wheat plot — 2 male and 4 female adults. 



Temperature. 



Shade. Sim 



Weather conditions. 



Observation on activity. 



A. M. 



8 



8.30 



9 



9.30 

 10 



10.30 

 11 

 11.30 



M. 

 12 



P. M. 

 12.30 



1 



1.30 



2 



2.30 



3 



3.30 



4 



4.30 



5 



5.30 



6 



6.30 



7 



7.30 



'F. 



106 

 114 

 118 

 116 

 104 

 114 



117 



111 



114 

 107 

 104 

 102 



Clear. 



Clear; wind rising . 

 •Clear 



Clear; slight wind. 



Partly cloudy; slight wind, 

 jpartly cloudy; no wind 



►Cloudy. 



►Cloudy; slight wind. 

 Clearing; less wind . . 

 ^Clearing; no wind . . . 



^Clear; no wind. 



2 feeding. 



3 feeding. 

 2 feeding. 



Do. 

 None feeding. 



2 feeding. 



3 feeding. 



Do. 



feeding. 



\ Do. 

 I Do. 

 5 feeding. 



Do. 



Do. 



Do. 



3 feeding. 

 Do. 



4 feeding. 



5 feeding. 



4 feeding. 



Do. 



5 feeding. 



5 feeding and resting. 

 Do. 

 Do. 

 Do. 



Observations made at various times during the night indicate that 

 the adults continue feeding after the daylight hours, providing that 

 the temperature remains high enough for them to continue their 

 activities. 



PREDACIOUS AND CANNIBALISTIC HABITS. 



In life-history cages the grain-bug adults frequently fed upon the 

 contents of their own eggs. Under these same conditions the adults 

 also fed upon the dead bodies of their companions and upon the 

 issuing dipterous parasite larvse. Apparently these predacious and 

 cannibalistic habits are abnormal, as no observations of a similar 

 character were made in the field, where on all occasions the nymphs 

 and adults were observed to feed exclusively upon plants. 



• GEEGARIOUSNESS. 



The grain bug exhibits a marked degree of gregariousness in hiber- 

 nation and to a more limited extent during its period of activity in 

 the field. In May, 1916, a total of 30 hibernating adults were found 

 under one " cow chip " about 6 inches square, and in the same vicinity 

 175 adults were collected from underneath the rubbish along a 20-foot 

 space in an irrigation ditch. When feeding in the field they appear 

 to prefer certain food plants to the exclusion of others of the same 

 kind and in the same stage of development. This characteristic fre- 



