THE WESTERN CABBAGE FLEA-BEETLE. \) 
LIFE HISTORY AND HABITS. 
OVIPOSITION. 
Opportunity was afforded for observing the female of this flea- 
beetle in the act of laying her eggs, beginning June 18, 1915, at Rocky 
Ford, Colo. In a period of 12 minutes 17 eggs were deposited. When 
fully extruded, the ovipositor is from one-third to one-half the length 
of the abdomen. The total time taken in laying an egg varied from 
2 to 5 seconds, 3 seconds being the average. During the laying there is 
a contracting movement of the abdomen, the ovipositor is extruded — 
not always to its full length — and an egg is forced through the 
opening. If, when the egg is forced out, it does not strike a surface 
and adhere to it the female twists the ovipositor about until the egg 
comes into contact with a surface to which it adheres. After an egg 
was laid the female generally ran about for a few seconds, then 
stopped and remained quiet for a few more seconds before laying 
another egg. Three different times the succeeding egg was laid at 
the same place within 3 or 4 seconds of the preceding one. As far 
as could be determined the eggs were not deposited in any particular 
order or arrangement, but were distributed quite promiscuously 
over the surface of the glass in the rearing cage. After having laid 
the last egg, the female ran down on the stem of a turnip leaf, which 
was in the cage, and commenced to eat. No further egg laying was 
observed, but as four other eggs were found it is presumed that they 
were laid before these observations began, which would give a total 
of about 21 eggs laid at this time. 
Subsequently eggs were found in various other locations, one mass 
of 20 being laid on the soil, another of similar number on the lower 
surface of a turnip leaf, while others were scattered in small masses 
about the crowns of the plants. 
The number of eggs that might be deposited by a single beetle was 
very difficult to ascertain and although attempts were made only 
two records of egg laying were obtained. 
September 6, 1915, three beetles, two females and a male, developed 
in the cages at Rocky Ford, Colo. They lived through the winter 
under bits of earth in a rearing jar, and March 29, 1916, the male 
mated with one of the females. This pair was isolated in another 
cage and the record of the eggs deposited is given in Table I. 
Table I. — Egg-laying record of a single female of Phyllotreta pusilla. 
Date. 
Number 
of eggs 
deposited. 
Date. 
Number 
of eggs 
deposited. 
1918. 
April 3 
21 
27 
23 
23 
16 
15 
1916. 
May 21 
25 
19 
32 
27 
21 
20 
12 
21 
29 
May 6 
29 
June 6 
13 
Total 
* 
244 
1832°— 20- 
