22 
THE BEAN THRIPS. 
LEAPING. 
This species possesses the power to leap actively and, considering 
its size, to a considerable distance. It is no uncommon occurrence for 
the specimens which are being examined" upon a plant to leap off and 
be lost. Like the greenhouse thrips, it will crawl over the leaves 
rapidly when disturbed. At other times it will remain motionless 
for a considerable period, lying closery to the surface of the leaf along 
one of the veins. 
NORMAL LENGTH OF LIFE. 
The length of life of this insect as an adult has been determined 
under the artificial conditions of confinement in vials containing 
fresh leaves of the food plant. As often as these lost their freshness 
other leaves were put in and the adults were changed with a camel V 
hair brush. 
Even under these conditions the length of life observed for some 
individuals was surprisingly long, when we consider the minute size 
of the insect. During these experiments it was observed that these 
insects were very sensitive to humidity or a lack of it and all were 
soon killed whenever the vials used in confining them became too dry. 
Table II shows the results of these experiments in which some thrips 
lived for 84 days. 
Table II. — Length of life of adult bean thrips wt Compton, Cal.,~ 1911. 
Date adults emerged from pupa. 
Number 
emerged. 
Specimens died. 
Date. Number. 
Last 
adult 
died. 
Maximum 
length of 
life. 
April 16 
April 23 
June 5.. 
July 19. 
/May 8 
\May 11 
"May 8 
May 18 
May 26 
June 5 
/June 17 
\June 21 
{July 22 
July 25 
July 26 
Aug. 8 
Aug. 12 
Aug. 17 
}May 
1 *JuIv 113 
1 
1 
J }Aug. 14 
2 
Days. 
84 
34 
i Dead. 
2 Lost. 
Male and female. 
LENGTH OF LIFE IN WINTER. 
A number of adults were collected from host plants on November 
18, 1910, and were placed in vials and furnished with fresh leaves at 
intervals, and some lived in confinement in this manner until Febru- 
ary 1, 1911, by which time all had died. On January 16, 1911. a num- 
