16 BULLETIN 436, U. S. DEPARTMENT 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. E. 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 actn^e. 
The hibernating adults may 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 
