124 
them onh^ two or three. It proved impossible to rear the parasites 
from most of these larvae, for the latter were nearly all affected with 
a bacterial disease and died before the parasites could attain full 
growth. 
The records are very meager, but serve to show that Tachinidfe are 
of but little assistance in controlling the boll worm. 
During the past season the life history of one parasite, Wlnthemia 
Ji,~iymtidata Fab. (see fig. 26), was worked out. A female kept in the 
laboratory deposited ^gg^ on three different bollworms, la^^ng five on 
one, seventeen on another, and one on a third. The eggs are 0.8 mm. 
in length, elongate-oval in shape, and pearly white at first, but after 
twenty-four hours they turn 
to an orange-3^ellow color. 
The duration of the life C3^cle 
is as follows: Egg, two days: 
larva, three days; pupa, nine 
to ten days. 
Summarizing the conclu- 
sions to be reached from a 
study of the insect parasites 
of the boUworm, it is evident 
that the destructiveness of the 
third and fourth generations 
is materialh' lessened h\ them. 
During September, 1904, when 
the fourth generation should 
have been damaoino- much of 
Fig. 26. — Winthemia U-pustidata: adult and parasitized 
moth pupa (original). 
the late cotton in northern Texas, it was almost impossible to find am' 
bollworms on cotton, and the few to be obtained in the neighboring 
alfalfa fields were invariably attacked bj^ parasites. At the same time 
adult specimens_of Microplitis could almost always be collected in these 
locations by the use of the sweep net. Meanwhile, the late corn nearby, 
where the parasites could not get at the larv^, was badly damaged. 
Such evidence plainly suggests that the dearth of larva? on cotton 
at this time must have been, in a measure at least, due to the good 
work of parasites. 
DISEASES. 
BACTERIAL DISEASE. 
There is only one disease that plaj^s an important part in the econ- 
omy of the bellworm. It is one evidently caused b}' bacteria, although 
its exact nature has not been clearly worked out. Its effects are most 
clearh' apparent among larva? feeding on corn, more especialh' those 
of rather large size. 
