50 OUR SHADE TREES AND THEIR INSECT DEFOLIATORS. 
cocoon by gnawing off and detaching a snugly-fitting cap. There are 
several secondary parasites of the Meteorus which we may mention later, 
and they always leave the cocoon of their host by smaller holes cut 
through the sides. Most of the adults had issued by the first of Novem. 
ber, but it is possible that some may remain in their cocoons until spring. 
‘‘ In order to obtain the proportion between the Meteorus raised from 
cocoons and its parasites, ¢. e. secondary parasites of Hyphantria, 450 
cocoons were confined in a glass jar the latter part of September. Up. 
to the first week in November only 70 specimens of Meteorus were bred 
from these cocoons, the rest giving out secondary parasites, which con- 
tinued to issue up to date of writing (December 20, 1886). Thus, only 
16 per cent. of the cocoons produced the primary, while 84 per cent.. 
produced secondary parasites. 
e 
Fic. 25.—An Apanteles: a, female fly; 6, outline of head of larva in posi- 
tion to show the chitinized parts of the mouth, the mandibles not visible, 
being withdrawn; c, one of its mandibles as seen within the head of a 
mounted specimen; d, cocoon; e, joint of antenna—all enlarged: uaturai 
size of a and d in hair-line. 
Apanteles hyphantrie Riley (Fig. 25).—“ This inseet was about as nu- 
merous as the Perilitus communis, and did equally good service in prevent- 
ing afurther increase of the caterpillars. It appeared somewhat earlier 
in the season, and killed only halt-grown caterpillars. From the nu- 
merous old and empty cocoons in early summer it was plainly seen that 
a first brood had been quite numerous, and that from these cocoons. 
mainly Apanteles had been bred, and not, as during the autumn, mostly 
secondary parasites. The white silky cocoon is formed almost under 
the middle of a half-grown caterpillar, and is fastened securely to the 
object its host happened to rest upon.and but slightly to the host itself, 
which is readily carried to the ground by wind and rain, and can there- 
fore only be found in position in the more sheltered places, such as 
cracks and fissures ot the bark of trees. But one Apanteles is found in 
a caterpillar, so that each white cocoon indicates, like a tombstone, the 
