22 
elasticity of these cocoons is extraordinary. It is almost impossible to 
open them without destroying their contents unless they are previously 
softened. The end from which the adult subsequently issues is the 
more pointed, and is usually lighter in color than the rest of the cocoon. 
The cocoon itself is attached to the leaf or bark by the coarser threads 
at the opposite end, and frequently this attachment is of such a nature 
that the cocoon hangs to a distance of several millimeters from its 
point of attachment. In issuing, the adult cuts off an even lid at the 
smaller end of the cocoon, the lid remaining attached by the coarser 
outer threads just mentioned as by a loose hinge. The dimensions of 
the cocoon are: Length, 4.8 mm.; greatest diameter, 2.2 mm. The 
period of development of this insect appears to be rapid, although we 
are able to give no definite figures. The larval development vertainly 
takes place in less than ten days, while in early autumn the pupa 
stage seems to vary from ten to twenty days. Owing to the extensive 
secondary parasitism, the method of hibernation was not ascertained. 
Adults were reared Sep- 
\ tember 19 to 23, but from 
the cocoons kept later in 
the season there issued 
only secondary parasites. 
Spilochaleis debilis, the hy- 
perparasite mentioned in 
connection with the Amor- 
phota, is also the most im- 
portant enemy of this 
| Species. 
Meteorus hyphantrize Riley. 
A single specimen of this 
common parasite of Hy- 
Fig. 9—Meteorus hyphantrie: a, adult female trom side; b, Dhantria cunea, described 
empty soeuas showing cap—enlarged (from Bull. 10, Div. by Riley in Bulletin No. 
Entom. U.S. Dept. Agr.). : anes 
; 10 of this Division, was 
reared September 25, 1895, from Orgyia leucostigma. The cocoon of this 
species is somewhat larger and of adarker brown than that of Meteorus 
communis, and it hangs suspended by a long strand of silk, as is well 
shown in fig. 24, Bulletin 10, here reproduced. In 1886, the great web- 
worm year in the District of Columbia, this species was very abundant. 
According to observations made that year, ten days elapsed between the 
completion of the cocoon and the emergence of the adult, and it was 
found that a majority of the adults had issued by November 1, making it 
probable that the insect hibernates in the adult condition. With this 
Speciesin 1886, as with the WM. communis in 1895, secondary parasitism was 
very marked. Out of 450 cocoons of the Meteorus placed in a glass jar 
the latter part of September only 70 adults issued, the remainder giving 
