CHRYSANTHEMUM MIDGE. 9 
Longevity of adults—In the life-history studies it was found that 
males usually live less than 12 hours, while the females live from 2 to 
3 days, in captivity and when not mated. Mated females probably 
do not live over 24 hours. In the case of three males which were seen 
to emerge after 1 a. m., all were found dead at 5.45 a.m. These re- 
sults are given in detail in Table I. 
Activity.—The males are not often seen on the wing, as they die 
shortly after mating, which takes place during the early morning 
hours, almost directly after emergence. When on the wing, how- 
ever, they are very active. The females, while generally rather 
sluggish, may show great activity at times, especially in the early 
morning and just prior to egg deposition. Dietz observed that on 
cool days when the temperature was 50° F. in the daytime, and cooler 
at night, the adult females were exceedingly active. Emergence rec- 
ords taken on many cages show that there are a somewhat larger 
number of females than males, the actual count being 464 females 
to 365 males. 
Egg deposition.—The female when laying eggs keeps her legs at 
equal distances apart and the ovipositor held at right angles to the 
rest of the body, beginning probably at the third or fourth abdominal 
segment. If not disturbed she acts with great precision. On one 
occasion a female was carefully observed during two operations, laying 
34 and 19 eggsrespectively. The first oviposition period lasted exactly 
3 minutes and 30 seconds, the second only 1 minute and 20 
seconds. An interval of only 10 seconds elapsed between the oper- 
ations. The tip of the long flexible ovipositor is thrust between the 
pubescent hairs of the young terminal growth and pressed down firmly 
on the surface. During deposition the eggs may be seen moving 
down the tube with great rapidity, accompanied by slight contractions 
of the ovipositor. Because of its darker color, the egg is plainly visi- 
ble through the walls of the ovipositor. The number laid at one time, 
according to Table II on page 10, varies from 5 to 135, with an aver- 
age of 32. Guyton (31) found that ‘‘the number deposited by each 
female is from 80 to 150.”” The eggs are usually placed in irregular 
masses, although they may be placed in strings or chains. During 
the whole operation the ovipositor is thrust around in a very nervous 
manner. At times when the female moves slightly about, the body 
is not straightened out but dragged along to the new place of deposi- 
tion, in the original bent position. Although egg-laying may take 
place up to and later than 4.30 p. m., the maximum egg-laying occurs 
from the early morning hours up to midday. The midges prefer to lay 
eges on the terminal growth of the plant on which they emerge, and 
particularly on the unfurling tip growth. This is true even in cases 
150054°—20—Bull. 833-2 | 
