46 
BULLETIN 427, U. S. DEPARTMENT OF AGRICULTURE. 
and on stored potatoes conditions are such that any parasite is of 
doubtful value. In addition, it seems to have one unfortunate habit, 
that of becoming at tunes a hyperparasite on Campo- 
plex plithorimaeac . This habit is so unusual, however, 
as to be unimportant. 
The record below gives the length of a life cycle : 
1915. 
August S.- 
August 16.- 
August 18.- 
August 25.- 
xVugust 26.- 
Au^ust 27.- 
- Tuber-moth larvae parasitized by Dibrachys clisio- 
campae. 
-Parasite Larvae mature. 
-Parasite larvae pupating. 
-4 parasite adults issued. 
-7 parasite adults issued. 
-1 parasite adult issued. 
(Male and female.) 
(Male and female.) 
(Female.) 
Fig. 42.— Dibrachys 
clisiocampae: Ma- 
ture larva. Much 
enlarged. (Origi- 
nal.) 
Length of life cycle 13 days at an average mean temperature of 
75° F. 
OTHER PARASITES. 
Other parasites ' were reared from time to time in 
small numbers from tuber-moth material collected in 
the San Gabriel Valley. They never became at all 
common. Efforts to rear them in the laboratory have 
been unsuccessful thus far. Both have been seen on 
occasion to oviposit in small leaf -mining tuber-moth larva 4 , but no 
parasites have issued, and so they have not as yet been proven to be 
parasites of the tuber moth. 
NEPEIRA BEXEVOLA VAR. EUSCIFEMORA CUSHM. 2 
For some time this parasite (fig. 44) was considered 
identical with Campoplex pJitJiorimaeae Cushm. The 
differences noted seemed to be variations within the 
species. While Mr. Cole was making drawings of the 
parasites, he noted that there were three separate types. 
Nepeira benevola var. fuscifemora Cushm. closely 
resembles Campoplex pJitJiorimaeae, both in appear- 
ance and life history, but has never become as abun- 
dant as the latter. It oviposits in half-grown leaf- 
mining tuber-moth larvae. 
Larva? parasitized November 12 have given adidt 
parasites December 12, a length of life cycle of 30 
days, at an average mean temperature of about 63° F. 
PERCENTAGE OF PARASITISM. 
Fig. 43.—Dibrach:;s 
clisiocampae: Pupa, 
lateral view. Much 
enlarged. (Origi- 
nal.) 
The percentage of parasitism has fluctuated so 
greatly in the time it has been under observation that 
it is difficult to give even approximate figures. The lowest parasitism 
noted was 40 per cent and the highest was 95 to 100 per cent. The 
i Chittenden Nos, 2230<»° and 2230°". 
2 Chittenden No. 2230°i2. 
