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THE DESERT CORN FLEA-BEETLE. 15 
time be protected from the heat. In feeding a beetle will stand 
crosswise on a corn leaf and with its strong mandibles eat out a 
portion of the epidermis between two parallel veins, continuing in a 
straight line, often 1 or 2 inches in length. They rarely eat a hole 
entirely through a leaf. In cases where extremely heavy feeding 
occurs and where the infestation is great, the green portion is entirely 
paten out, and the leaf has a burned or scarred appearance. 
SEASONAL HISTORY. 
NUMBER OF GENERATIONS ANNUALLY. 
The desert corn flea-beetle usually appears about the middle of 
February each spring. The time at which the beetles may first be 
found actively feeding in the field will, of course, depend upon the 
season. In the year 1912 Mr. R. N. Wilson first took these beetles 
on February 14, sweeping a few specimens from a barley field. In 
1913 the same observer took a few feeding beetles on January 13. 
The month of January of that year, however, was quite warm and 
advanced over the ordinary year. In the year 1914 Mr. D. J. Caffrey 
took adults for the first time on February 20. These were feeding in a 
green wheat field. In the spring of 1915 Mr. F. H. Gates first swept 
adults in an alfalfa field on February 9. They did not, however, 
become abundant until February 23, when both the author and 
Mr. Gates secured an abundance of this species. 
It is only a few weeks after emergence that these hibernating 
adults begin depositing eggs. The earliest date that eggs have been 
secured in cages was March 12, 1915, at which time the writer secured 
eggs in considerable numbers. There are from three to four genera- 
tions each year in the Salt River Valley. The first generation, starting 
with eggs deposited in early March, appears about the first of June. 
Another generation quickly follows, adults co: ling forth about the 
middle of July, a third generation is completed by the first to the 
middle of September, and in occasional years there is a partial fourth 
generation. 
The fact, however, that the length of each individual life cycle is 
determined quite largely by the proximity of both larvae and pupae 
to the surface of the ground is responsible for the general inter- 
mingling of the various generations, so that eggs may be secured 
throughout the breeding season. Eggs have been secured in cages 
throughout the year, beginning with the first of March and continuing to 
the middle of October. Mr. Wilson has secured eggs in cages during the 
months of May, June, July, August, September, and October, while 
the writer has secured eggs during March, April, May, and June, and 
these records were followed up by those of Messrs. Hogg and Newton, 
who obtained eggs during July, August, and September of the same 
year. Of course, eggs deposited the first of October would, ordi- 
