14 BULLETIN 1469, U. S. DEPARTMENT OF AGRICULTURE 
fish oil, or, if this is not available, the same quantity of raw linseed 
oil, to each 400 gallons of spray. The oil should be poured into the 
spray tank while it is being filled with water and after the poison has 
been added. The contents of the tank should be thoroughly agitated 
while the oil is poured in and until the mixture is applied. 
This spray will adhere very closely to the foliage and is affected 
very little by rain. Care should therefore be exercised to prevent 
cattle from feeding on the grass beneath sprayed trees. Buildings 
will be discolored with this spray unless care is taken to wash them 
with water from a garden hose before any poison adhering to them 
is thoroughly dried. 
NATURAL ENEMIES 
One of the interesting features of the introduction of an insect 
into a new region is the question whether it will be attacked by 
natural enemies present in its new home. 
NATIVE PARASITES 
Several native parasites have been found attacking the satin moth 
in New England, although the rate of parasitism is small. The 
following species were reared from this insect at the Gipsy Moth 
Laboratory : 
Reared from eggs. — Telenomus calif ornicus Ashm. 
Reared from larvw. — Zenillia blanda O. S., Frontina frenehii Will., and Phoro- 
cera claripennis Macq. 
Reared from larvw and pupas. — Taehina- mella Walk, and Winthemia quadri- 
pustulata Fab. 
Reared from pupw. — Theronia fulvescens (Cress.), Ephialtes pedalis (Cress.), 
Itoplectis conquisitor (Say), and Dibrachys hemerocampae (Girault). 7 
Of native parasites Telenomus calif ornieus is the most common. 
During the summer of 1925, satin-moth egg clusters were received 
at the laboratory from 66 towns in New England, from 19 of which 
this egg parasite was recovered. These data are especially interest- 
ing, as the collections, each consisting of a single egg cluster, were 
mostly taken from new infestations in towns on or near the border 
of infested territory. 
Two species of Tachinidae, three species of Hymenoptera, and 
three sarcophagicls have been mentioned as natural enemies of the 
satin moth in British Columbia. The tachinids T. mella Walk, and 
T. robusta Tn. appear to be of considerably more value there than 
an}^ native parasite has been in New England. Glendenning 8 writes 
as follows of observations made in 1922 of infestations in New West- 
minster, British Columbia, where from 25 to 80 per cent of the 
caterpillars had tachinicl eggs on them : 
The majority of these eggs, being laid shortly after the last larval molt, 
hatched before being shed at pupation, and the great majority thus proved 
fatal to their hosts and were an appreciable control factor in this location. 
Another quotation from Glendenning 8 follows, indicating the 
abundance of native tachinids at an infestation on Vancouver Island. 
7 Determined by A. B. Oahan, of the Bureau of Entomology. The other Hymenoptera 
and Diptera were determined by C. F. W. Muesebeek, R. T. Webber, and T. H. Jones, of 
the Gipsy Moth Laboratory. 
8 See p. 13 of publication cited in footnote 3. 
