25 
autumn its cocoons were found to contain, in the main, secondary para- 
sites. When affecting Hyphantria, the white silken cocoon is formed 
almost under the middle of the half-grown caterpillar, and is fastened 
securely to the object its host happens to rest upon and slightly to the 
host itself, which is, however, readily carried to the ground by wind 
and rain, and can therefore only be found in position in the more shel- 
tered places, such as cracks in the bark of trees. But one Apanteles is 
found in a caterpillar, so that each white cocoon indicates the death of 
a victim. The cocoon of this species is readily distinguished from that 
of the foregoing species by its denser consistency, its apparently tougher 
silk, and greater opacity. The cocoon of Apanteles delicatiis is, moreover, 
more firmly attached to the bark of the tree upon which the host insect 
has been feeding and by a greater number of attaching threads, as 
shown in fig. 11. 
In the summer of 1895, as will be noted later, the larvae of the fall 
webworm were frequently found (usually in the half-grown condi- 
tion) wandering about the trunks of trees affected by the Orgyia, this 
peculiar condition of affairs resulting mainly from the destruction of the 
food supply by the very unusual numbers of tussock-moth caterpillars. 
Apanteles hyphantrice was very abundant, and a large proportion of 
these wandering, unprotected half-grown webworms were stung by this 
species. It happened in a number of cases that tussock-moth cater- 
pillars of a corresponding stage of growth were also stung, and it can 
definitely be said that this Apanteles, while apparently preferring the 
webworm, is also a true primary parasite on occasion of the tussock- 
moth caterpillar. Its habits when attacking this latter host are similar 
to those just described. Its cocoons were abundant upon the tree trunks 
during the winter of 1890-97, and examination showed that they were 
almost without exception infested by hyperparasites. Among these 
were recognized Elasmus atratus (by far the most abundant), Dibrarftys 
bouclieanus, and Spilochalcis debilis. Aseeodes albitarsus was also in 
one case reared from a cocoon which had been infested by Dibravhys 
boucheanus, 
Chalcis ovata Say. 
This widespread species, which is found all over the United States 
and Canada, and which also extends into the West Indies, is a very 
general parasite of Lepidoptera, issuing as a rule from their pupre. 
The writer in 1835 (Bulletin Xo. 5, Division of Entomology) recorded 
it as having been reared from pupa* of Thyridopteryx ephemercvformis, 
Apatura clyton, Aletia argillacea^ Desmia maculalis, Caccecia rosaceana, 
Gelechia gallw-solidaginis, and Botis alnialis. It is rarely parasitic on 
the fall webworrn (Hyphantria cunea), but is the most important of the 
primary parasites of the tnssock-moth caterpillar next to Pimpla 
inquisitor. 
It was first observed ovipositing in the tussock-moth cocoons on Sep- 
tember 7, 1895, when the writer observed it in some numbers flying 
