May 5,1923 
Striped Sod Webworm 
411 
writer has seen. Each of the median segments bears from 14 to 18 sen- 
soria (PI. 2, A) compared with 8 or 10 in hemiochrellus. The male genita¬ 
lia give the best basis for comparison. The free costa, which in hemiochrel- 
lus is a stout naked spine as long or longer than the sacculus, is in mutabilis 
a small slender spine less than half the length of the sacculus, which 
remains practically the same. The tegumen and uncus retain much the 
same shape, but the cornutus (PI. 2, E) in the aedoeagus is both shorter 
and more slender than in hemiochrellus. The wing shape and the general 
uniform coloration remain similar in the two species, and the eggs of the 
two assume and retain exactly the same color during the incubation 
period. 
NATURAL CONTROL 
That this species has not more frequently been recorded as a destruc¬ 
tive pest is probably due to two factors—the apparent great suscep¬ 
tibility of the larvae to disease, and the attacks of parasites. 
DIS^ASKS 
While making intensive studies of this species at Nashville, Tenn., in 
rich blue-grass meadows, where the larvae were known to be abundant, 
areas were often found in which practically every burrow contained only 
the flaccid dead body of the maker. The same disease, evidently bacterial, 
was met with in the laboratory, and it was only by using the strictest care 
in the sterilization of the tin boxes used as rearing cages that it was pos¬ 
sible to bring the larvae to maturity. The disease first manifests itself in 
the lack of appetite and sluggishness of the larva. The next day the larva 
is dead and somewhat softened, but not externally changed. Another 
day reduces it to a shapeless sack filled with a dark brown semiliquid. 
Finally the skin also breaks down and the mass gradually dries up, leaving 
only a dark stain. The writer has not succeeded in getting a determi¬ 
nation of the cause of the disease, but that it plays a very large part in 
keeping this species from becoming a serious pest can not be doubted. 
Another disease which is less common kills the larva more gradually. 
It usually begins at the caudal end and leaves it corky in texture and 
densely filled with a mass of whitish hyphae. The fungus causing it has 
been determined by Dr. A. T. Speare as a species of Isaria. 
PARASITieS 
Because of the fact that the larvae of this species have a more open 
method of feeding than some of the others, they appear to be more 
subject to the attacks of parasites than those which remain more con¬ 
stantly underground. 
Two species of tachinid flies have been reared from larvae of Crambus 
mutahilisy namely Phorocera claripennis Macq. and Exorista nigripaipis 
Towns., neither of which apparently has heretofore been recorded from 
this host. Both were reared from larvae collected by W. H. Larrimer in 
connection with an outbreak of web worms near La Fayette, Ind., in June, 
1920, in which two species of Crambus were concerned, C. trisectus and 
C. mutabilisy the former predominating to the extent of about 80 per 
cent of the total. 
Fifteen flies of the species Phorocera claripennis Macq. were reared 
from 14 host larvae, two of them maturing, in one instance, from one host. 
