68 NINETEENTH REPORT STATE ENTOMOLOGIST OF MIN NESOTA—I1922 
the gregarious instinct in Perillus is sometimes apparent in their 
hibernation habits. 
Under natural conditions the bugs come forth from hibernation 
during the first warm days of spring, or very shortly after the frost 
leaves the ground. At St. Paul, the earliest capture in the field was 
that of a red male taken on the sidewalk on May 7, 1920. In New 
York, the earliest field record was the capture of a female specimen, 
on April 17, 1915, at Batavia. Several specimens have been taken in 
buildings in April, and one bug was found active in February at the 
window of a heated room. 
The condition of the bugs when they go into hibernation has much 
to do with the chance they have of passing the winter successfully. 
This condition depends on the activities of the bug, the amount of 
food taken, and the temperatures to which the bug has been subjected 
just previous to the time when it becomes inactive for hibernation. 
In handling various lots of bugs for hibernation it was noticed that 
some were much more successful in passing the winter than others. 
This may best be shown by giving actual figures on three lots of bugs 
selected from a large series kept for hibernation. 
Lot A contained 27 bugs, 10 males and 17 females, all of which 
had matured in August. Beginning with September 1, these bugs, 
confined in jars without food, were kept in a cool situation which dur- 
ing September averaged between 60° and 68°F. On October 1 they 
were placed in cold storage where the temperature was gradually low- 
ered until by October 15 it had reached 41°F. The temperature of 
the hibernating chamber ranged between 41°F. and the freezing point 
until the following May. Upon examining the jars on October 19, 
it was found that all were alive except 4 males and 3 females. An 
examination of this lot of bugs on May 19, 1922, revealed the fact 
that 3 males and one female had died since October 109, thus leaving 4 
males and 12 females that had passed the winter successfully. These 
figures show that 59 per cent of the bugs passed the period of hiberna- 
tion and came forth alive. 
Lot 207 was composed of 15 bugs, 7 males and 8 females, which 
were kept active and given all the food desired as late as September 
10. The bugs were then placed under similar conditions with Lot A. 
An examination of these specimens on October 19 showed that 6 
males and 3 females were dead. When examined on May 19, 1922, 
only one male and one female were left alive. In this case only 13 
per cent of the bugs survived the period of hibernation. 
Lot 218 numbered 86 miscellaneous bugs collected in the field 
on September 1 and 2. These bugs were kept alive in jars with plenty 
