36 BULLETIN 1374, IT. S. DEPARTMENT OF AGRICULTURE 
Their life history and habits were studied during the summer by 
A. C. Johnson and are here given briefly, so far as known. 
Normally the female M. mellitor stings the pink bollworm larva 
while still in the square, paralyzing it, and deposits an egg on it. In 
all cases only a single egg was found on one larva. When placed in 
a cage the adult did not attack loose pink bollworm larvae. The 
larva of the parasite feeds on the pink bollworm until nothing is 
left of the latter but a mass of dry skin. 
The larval period of M. mellitor was found in the summer to be 
from 33^ to 4 days. The pupal period lasted 4 to 5 days. The 
adult of this species is apparently a nocturnal worker, as none were 
ever observed in the field in the daytime. 
Habrobracon gelechiae is more common through the season than 
M. mellitor. In freshly opened blooms, larvae of the pink bollworm 
attacked by this parasite were usually found paralyzed and with 
the eggs of the parasite on them. This indicates that the attack is 
made after the bloom opens, which appears likely also when we 
consider the short ovipositor of the adult. It is common to find 4 
or 5 eggs on 1 larva, and as many as 10 have been observed. In 
some instances the adult attacked loose pink bollworm larvae in 
cages. 
The larval and pupal periods of H. gelechiae are about the same as 
those of M. mellitor. Many adults of the former were observed in 
the field in the daytime. 
About two-thirds of all paralyzed pink bollworm larvae found in 
blooms contained neither parasite eggs nor larvae. It is possible 
that in such cases the eggs or larvae were destroyed by other insects, 
or the adult of the parasite may often sting the pink bollworm with- 
out depositing eggs upon it. 
On October 2, some clusters of cocoons and several living pupae of 
H. gelechiae were found in dry blooms collected from the ground. 
Then 400 closed blooms from 2 to 5 days old were collected from 
plants. Ninety-seven of these were infested with pink bollworms, 
of which 10 were parasitized by H. gelechiae. About 2 per cent of 
the larvae found in bolls in the fields in December, 1921, were para- 
sitized by H. gelechiae. These observations show that H. gelechiae 
seems to prefer attacking larvae in dry blooms and bolls in the fall 
to attacking them in fresh blooms. During 1921, M. mellitor was 
more abundant early in the season. 
Several other species of parasites were reared from pink bollworm 
larvae. These were rare and have not been identified. 
General observations showed that the parasites were not so 
abundant in 1922 as in 1921. A few parasites apparently identical 
with M. mellitor were reared from malvaceous plants other than 
cotton in 1922, but what insects these parasites attacked was not 
determined. H. gelechiae was not observed emerging from these 
plants. 
The more or less spasmodic attack of parasites on the pink boll- 
worm observed in 1921 and 1922 indicates that under conditions 
existing in the Laguna district no appreciable control of the pest by 
parasites may be expected, even though a maximum of 33 per cent 
of the larvae in blooms early in July, 1921, were parasitized. Climatic 
conditions are evidently much more favorable for the pink bollworm 
than for the parasites so far observed. 
