1906] 
GIRAULT—TRICHOGRAMMA PRETIOSA RILEY 
143 
number of eggs laid, leads to the enormous number of one thousand and eighty 
(1,080). The average length of life of a female was here limited to two days, the 
average length of the period of oviposition to thirty-six hours, and the average time 
for single depositions to two minutes. 
It is important to take into consideration the fact that in nature the host eggs are 
well scattered, and that the little Trichogravima has to take considerable time and 
much pains to find them. For such a minute insect, the examination of a whole leaf 
of corn is no small undertaking. 
5. Number of eggs deposited into single hosts. This was determined both by 
direct observation and by rearing experiments. 
By direct observation, much data was obtained but was hardly worthy because 
of the conditions prevailing in confinement. Females were observed several times 
to deposit as many as five eggs into a single host, but all of these did not successfully 
develop. 
On this point, the following results were obtained by rearing exj)criments made in 
the laboratory at Paris. The hosts were obtained from corn and cotton. 
Date, 1904- 
May 6th. 
iNIay loth. 
May 16th. 
May 31st. 
Host No. 
1 . 
2 , 
3. 
4. 
5. 
6 . 
7. 
8 . 
9. 
10 . 
11 . 
12 . 
13. 
14. 
15. 
16. 
17. 
IS. 
19. 
Number parasites emerging. 
4. 
3. 
3. 
4. 
1 . 
1 . 
2 . 
5. 
3. 
2 . 
4. 
4. 
2 
2 . 
3. 
4. 
5. 
1 . 
4. 
