117 
corn, which in 1904 was about the middle of May in northern Texas. 
After this time there is always a continual supply of eggs, owing to 
the laying by belated moths of the spring generation; and through- 
out the season the smaller number of eggs between the more marked 
generations serve to furnish a continuous supply of food for the 
parasites. 
Experiments were conducted in the laboratory by Mr.* Girault to 
ascertain the length of the life cycle of Trichogramma and the number 
of broods during the season. The first generation, started on May 
26, required eleven days, but the time for the succeeding generations 
graduall}^ decreased to eight days during Jul}^ and August, and length- 
ened to eleven again by the beginning of October. During the whole 
summer some fifteen consecutive generations were under observation. 
Some of the adults of the fifteenth generation apparently do not emerge 
from the pupa state, although a large proportion of them do. These 
ma}^, under favorable conditions, produce other scattering broods, but 
it is probable that most of them must die before finding eggs which 
they can parasitize. Those remaining in the pupa stage no doubt 
hibernate in this condition, not emerging until the beginning of the 
following summer. 
When a boUworm egg is discovered by the nervous little Tricho- 
gramma, as she darts about in search for one, she will quickly examine 
it by crawling over the surface and tapping it with her sensitive anten- 
nae. If it seems suitable to her, she quickly sets about inserting her 
thin, flexible ovipositor at the desired spot. After about half a min- 
ute this has pierced the thick shell and is well within the egg^ allowing 
the parasite to deposit her egg near the center of the bollworm egg. 
The ovipositor is then withdrawn and the parasite is ready to repeat 
the process. The laying of each egg requires about two minutes. 
On several occasions we have seen Trichogramma ovipositing in the 
field. The procedure seems to be essentially the same as that observed 
in the laboratory, but necessarily rather hard to observe without the 
aid of a rather powerful lens. Ap])arently the insect has no means of 
ascertaining whether a bollworm egg has alread}^ been parasitized, 
since eggs known to contain Trichogramma eggs are often selected by 
a second female for oviposition. This second parasitization, however, 
seems to occur onh^ before the egg begins to turn black, which would 
suggest that the Trichogramma detects an egg already parasitized by 
its dark color. 
It the laboratory it was found that the Trichogramma could be 
raised on infertile bollworm eggs, although the latter normally shrivel 
up shortly after they are laid. As infertile eggs are laid very rarel}^ 
in nature, this discovery is of more scientific than practical value. 
Mr. Girault's observations tend to show also that Trichogramma may. 
