56 NINETEENTH REPORT STATE ENTOMOLOGIST OF M{NNESOTA—IQ22 
leaves from drying out too rapidly. One pair of bugs in a glass will 
take very kindly to this arrangement, and when fed daily will produce 
eggs quite as freely as in the field. After the bugs have been confined 
in the jars for two or three weeks they become very tame, rarely try 
to fly when handled, and show little fear as they walk about on the 
hand or table. The female bug will lay her eggs on the potato leaves 
when provided, but in the absence of these, will lay eggs readily on the 
sides of the jar or on cheesecloth when it is supplied. The bugs 
should be fed once or twice each day, altho they will get along if 
neglected for a day. As fast as the eggs are laid they may be removed 
to new jars for rearing. After the nymphs attain the third instar it 
was found best not to keep more than six or eight in one jar. Unless 
plenty of food is available at all times the bugs may develop canni- 
balism. The unfortunate victim is usually attacked when in the act 
of molting. However, when the bugs are not overcrowded this diffi- 
culty rarely occurs. It was found necessary to clean the breeding 
jars frequently, especially when rearing nymphs on larvae of the potato 
beetle. For the purpose of keeping records, labels were pasted on the 
sides of the jars, or attached to the lids. 
Life History 
Life cycle-——The adults of Perillus come forth from hibernation as 
soon as the ground thaws out in the spring. By the time the potato 
plants show above ground, and the first potato beetles appear, Perillus 
may be found congregating in the potato fields. Their first meal in the 
spring is sap from the potato plant, but after that their food is almost, 
if not exclusively, the body fluids of potato beetles, their eggs and 
larvae. 
Perillus lays its eggs in masses on the leaves of the potato plant. 
These hatch within five or six days, according to the temperature. 
In the second instar the nymphs begin feeding on eggs or small larvae 
of the potato beetle and as the bugs grow in size, large grubs and even 
beetles fall as prey. The nymphs pass through five stages or instars 
before attaining the adult stage; the average length of nymphal life 
being 19 days during July and August, and 22 to 24 days during Sep- 
tember. Upon reaching the adult stage the bugs begin mating, and 
the females may start laying eggs six or seven days thereafter, 
In New York, the first brood adults were found mating in the 
field July 9 and 10, 1914. One pair of these laid eggs on July 16, 
and from this lot adults matured August 9. This lot of bugs, or the’ 
second brood, laid eggs that matured the third brood during September. 
Thus three broods of Perillus matured when the first brood eges were 
