16 BULLETIJSr 436, V. S. DEPAETMENT OF AGRICULTURE. 



narily, not reach maturity, while those deposited in the middle of 

 September in some seasons develop a partial fourth generation. From 

 October 13, 1914, to March 9, 1915, the writer maintained in a labora- 

 tory cage a large number of Chaetocnema adults which had been 

 collected from the field, but did not secure a single egg during this 

 time. 



HIBERNATION. 



From the foregoing remarks on the generations it is at once seen 

 that these adults usually are found hibernating during the latter 

 part of November, in December, and in January. They enter hiberna- 

 tion gradually during November, and one is rarely able to find adults 

 throughout December and January, although on an occasional warm 

 day specimens might be secured during any winter month. On Nov. 

 7, 1912, at Tempe, Ariz., Mr. R. N. Wilson made the following note: 



Only a few Chaetocnema could be found on corn on the Godfrey field to-day. 



Then on November 23, 1912, he made the following observation: 



The corn on the Godfrey field has been cut since the field was last visited. No 

 specimens were found. 



On December 14, 1914, also at Tempe, the writer observed adults 

 in hibernation and made the following record: 



A few Chaetocnema adults were found to-day in protected places, as back of sheath 

 leaves, in an old cornfield, and at the base of wild barley plants that thickly covered 

 the ground. The species is apparently very quiet at this time and can be said to be 

 hibernating. The past week has been rather cold and several mornings the tem- 

 perature fell to considerably below freezing. One or two specimens were noted, how- 

 ever, that appeared quite active. 



The hibernating adults miay be found beneath anything that will 

 give them protection, such as rubbish and grass clumps in waste 

 places. A favorite place for adults to winter is along ditch banks 

 thickly grown up with Bermuda and Johnson grass. These places 

 seem to be ideal because, late in the winter or early in the spring, 

 they become overgrown with wild barley, and this plant gives the 

 beetles succulent food the first warm days in the spring. Waste 

 salt places which are not too wet and are grown up with salt grass 

 also afford ideal conditions for hibernation quarters, and the beetles 

 have been observed on this grass quite early in the spring. Early in 

 1912 Mr. R. N. Wilson made the following note: 



At the northeast corner of this farm there is a large patch of salt grass (Distichlis 

 spicata), which forms a thick mat on the ground. Sweepings made on this grass 

 to-day revealed many Chaetocnema. This is likely one of their food plants, and 

 probably furnishes an ideal place for hibernation. 



NATURAL ENEMIES. 



Judging from our present knowledge of this species, it seems to be 

 fairly free from the attacks of enemies of any kind. While it is quite 



