THE SATIN MOTH, A RECENTLY INTRODUCED PEST 
17 
in the localities represented. Sufficient study has not been made to 
determine that. 
Table 2. — Parasitism of satin-moth larvm by Compsilura concinnata in New 
England in 1925, as shown by rearings 
Town 
Larvae 
collected 
Comp- 
silura 
recovered 
1 
\ i 10, 680 
3,062 
200 
29 
54 
16 
1 
Eastham. .-.______--- -- - .- - - ..-...- 
1 
Total - 
10, 963 
3,080 
1 In the laboratory experiments several collections from these three towns were combined. 
In addition to the larval collections shown in the foregoing tables, 
dissections were made of medium and large-sized satin-moth larvae 
collected at the towns listed in Table 3. 
Table 3. — Percentage of satin-moth larva? parasitized by Compsilura concin- 
nata in New England in 1925, as shown by dissections 
* 
Town 
Larvae 
collected 
Larvae 
para- 
sitized 
Percent- 
age of 
larvae 
para- 
sitized 
150 
1 
200 
3 
200 
50 
16 


87 
2 
2 
8 
6 


43.50 
66.67 
Seabrook, N. H__ 
1.00 
Concord, N. H_ - - 
16.00 
37.50 
Total 
620 
105 
16.94 
The larval dissections listed in Table 3 show in a number of cases 
more than one parasitic maggot in each caterpillar. Such superpara- 
sitism by Compsilura occurs in a number of different hosts, and, 
although it is a waste, it is not as disastrous as might appear. In 
the case of the satin moth and of several other species superpara- 
sitism is seldom excessive, and the host is large enough to support two 
and sometimes more Compsilura maggots without apparent weaken- 
ing of the resulting adult parasites. 
One hundred satin-moth larvae were collected at Quincy, Mass., 
in 1924, and upon dissection were found to have an unusual degree 
of superparasitism. Forty-two contained no parasites, but the re- 
maining 58 were parasitized by 77 Compsilura maggots. It seems 
evident that Compsilura larviposits in its host at random, and in 
this case an unnecessarily large number of parasites were present 
in some of the hosts. Each of 35 larvae contained 1, each of 13 con- 
tained 2, and 1 contained 3, first-stage maggots; 7 were found to 
