8 BULLETIN 922, TJ. S. DEPARTMENT OF AGRICULTURE. 
mild weather between December 20, 1915. and February IS, 1916. 
Since eggs laid after November 13, in 1915, failed to hatch the follow- 
ing spring, it appears that partial development of the embryo previous 
to cold weather is necessary to enable the egg to survive the winter. 
Approximately 30 per cent of the eggs overwintering in vials hatched, 
but it is probable that this is below the normal under natural 
conditions. 
The eggs, which are a watery yellow when laid, soon grow darker yel- 
low and early in the fall turn dark in from 2 to 6 days. The last laid 
eggs may retain their yellow color through the winter, all development 
being arrested. Early in the fall the eggs that have darkened become 
sculptured in a day or two, but later on the time elapsing between 
these changes may be lengthened to weeks or months. The next no- 
ticeable change in the egg is the rapid pigmentation of the head of 
the embryo which appears beneath the shell as a distinct round black 
spot. In the early fall the egg hatches in from 1 to 3 days after this 
change, although later such eggs may go through the winter in this 
condition or may hatch during some of the mild winter days. 
During the fall of 1915 the shortest egg period was 13 days, the 
eggs being laid September 10, and the longest period, excepting for 
overwintering eggs, was 46 days, the eggs in this case being laid 
October 21. The average of the records of 50 lots of eggs between 
September 8 and October 21 was 25.8 days. 
Just previous to hatching the embryos are active within the egg 
and can be seen moving around. They emerge by cutting a small 
round hole large enough for the larva to pass through, usually near 
one end of the egg. The eggshells are never eaten by the larva? after 
they have emerged. The larva? will commence feeding at once if 
placed on clover leaves, but may live a long time without food, as in 
the case of those hatching during the winter. The length of the 
larval stages is very variable in the fall, for feeding is suspended 
during adverse weather and resumed in mild. The shortest time 
secured for the first stage was 13 to 14 days, for the second stage 
12 to 14 days, and for the third stage 10 days. No fourth-stage larva? 
were obtained in these experiments during the fall as the cold weather 
sent the larva? into hibernation. Table II summarizes the lengths of 
the different stages and larval instars as observed at La Fayette, 
Ind., in the spring and early summer. 
Numerous larva? were collected on different dates during the 
winter to determine the ages of the wintering larva? and the results 
of such collections are given in tabular form in Table III. No 
adults were found by the authors but Folsom (3) records that hiber- 
nating adults collected in the spring were much enfeebled and unable 
to lay eggs. He suggests the possibility of a second generation of 
beetles farther south which hibernate and oviposit in the spring. 
