2/4 MAINE) AGRICULTURAL EXPERIMENT STATION. 1907. 



have been tossed np along the ridge. At the right of the field . 

 is an uncultivated piece of land, part swamp and part wooded 

 knolls, along the slopes of which the fallen leaves are caught 

 in drifts. Search was made in the spring, May 6-8, before their 

 hibernating pests were on the wing in this locality, and though 

 tarnished plant-bugs were found in considerable numbers under 

 the leaves at the right of the field where predaceous beetles 

 were not present to any great extent, at the left, equally favor- 

 able hibernating ground to all appearances, these insects were 

 found in the proportion of 1 to several hundred ground-beetles 

 and rOve-beetles. The inference was acted upon by collecting 

 the beetles for laboratory observations as to their diet. The 

 ground-beetles were the common Carabid species, Pterostrichus 

 lucublandus Say. 

 Test with a lot of 22 ground-beetles. 



May 11. They were given one Cosmopepla carnifex which 

 they did not eat until May 18. 



May 13. They were given 2 negro bugs (Corimelcena puli- 

 caria). These they devoured May 15. 



May 14. They were given 6 sowbugs. May 18 only one 

 live sowbug was left and a beetle was carrying off bits of a 

 sowbug. 



They showed no eagerness in regard to any of the foregoing 

 insects. May 18, however, they became much excited upon 

 being given an inch-long moth pupa. They tried patiently to 

 bite it, but the pupal skin was particularly hard and it slipped 

 about so that it had to be finally cut for them. In less than a 

 minute 20 of the 22 beetles were either feeding upon the pupa 

 or fighting violently for a chance. They hauled one another 

 off by the legs and were very much excited and vicious, the 

 taste of this food seeming to make them tigerish. They had 

 been stupid for a week previous. While they were still excited 

 over the one-inch pupa they were offered a cecropia pupa taken 

 uninjured from the cocoon. This they attacked at the abdom- 

 inal creases and succeeded in biting through. After gorging 

 at this feast the beetle abdomens protruded beyond the wing 

 covers for more than one-sixteenth of an inch, giving them a 

 peculiar appearance. 



