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freshly emerged beetles in the field. The latest date for their emer- 
gence may be given as July 15. Many beetles issue daily from June 
5 to June 30, and most of the beetles issue during the last week of 
June. 
Early as the beetles appear, they do not begin to mate until the last 
week of August, and nearly all the eggs are laid in September and 
October. 
We have insectary records of oviposition for almost every day be- 
tween September 17 and October 26, and almost daily records of 
hatching from October 9 to November 27. The egg period in autumn 
is from 23 to 45 days, averaging 29 days ; the length of the period de- 
pends upon temperature chiefly; some of the latest eggs, indeed, 
do not hatch until the following spring. Out-of-doors we have found 
eggs as late as November 14, and young larvae as early as October 10. 
After that date they soon become common, and can be found at any 
time during the winter between the bases of the clover stems, as deep 
as possible, or else on the ground under more or less protection. Many 
of them succumb to the cold, however. These winter larvae also are 
of various sizes. Sixty-five larv?e measured November 26 ranged in 
length from 2.5 mm. to 7.5 mm., with an average of 3.17 mm. 
Late in October a few living beetles — more than three months old 
— occur in the clover field and go into hibernation. Early in the fol- 
lowing spring their dead bodies may be found. Earther south, it is 
possible that enough beetles survive the winter to influence the course 
of the life history. 
The preceding general account of the life history is based upon 
such a large body of observations that it represents the actual condi- 
tions with considerable accuracy, for central Illinois. A few precise 
notes are added on account of their significance. 
Many eggs laid between October 16 and 25, 1905, were apparently 
sound January 21, 1906, and had not hatched February 23; but 
March 21, young larvcie from them were found, still alive, and 2 mm. in 
length. Again, eggs laid October 26, 1904, did not hatch until April 
13, 1905. 
I have several times followed the consecutive life history for a 
year or more. The longest account, covering a period of eighteen 
months, begins with a female beetle taken September 23, 1904. She 
laid eggs as follows : 
Sept. 26, one mass of eggs. 
Oct. 1, three egg-masses; hatched Nov. 3 and 4; larvae alive Nov. 
21, but died during winter. 
Oct. 9, several eggs laid ; they hatched November 19 ; the larvae 
died in winter. 
Oct. 26, several eggs laid; unhatched April 12, 1905; hatched 
April 13. 
Nov. 1, three eggs; hatched Nov. 27, in warm room. The mother 
was alive Nov. 21, but died during the winter. 
The larvae that were born April 13, 1905, were reared ; they buried 
