THE ALFALFA CATERPILLAR. 
25 
scribed by him x as new. This is supposedly a new record of habit 
for this species, but according to Mr. Wilson it was reared time and 
again from pupse which were alive when collected; thus the flies 
could not be acting as scavengers, but must have been true parasites. 
OTHER INSECT ENEMIES. 
Fig. 16. — Bollworm (Heliothis obsoleta), an 
enemy of the alfalfa caterpillar. Twice 
natural size. (Author's illustration.) 
A large green caterpillar, known as the bollworm, Heliothis obso- 
leta Fab. (fig. 16), which can be 
distinguished from the alfalfa 
caterpillar because it is of a 
lighter green color, about one- 
fourth larger, hairy, and rough 
in appearance rather than 
smooth, with three black lines 
traversing its body lengthwise, is quite prevalent in the Imperial 
and Salt Eiver Valleys, and is often mistaken for the alfalfa 
caterpillar by many farmers. As observed by the writer, and later 
by Mr. T. Scott Wilson, it was found to do very little damage to al- 
falfa, but to be a ravenous enemy of the alfalfa caterpillar, never eat- 
ing alfalfa as long as it could find the larvse 
or pupse of Eurymus. Messrs. E. O. G. Kelly 
and T. H. Parks noted this species at Welling- 
ton, Kans., in the summer of 1909, and re- 
ported it as being of a predaceous habit. 2 
The writer observed a bollworm larva to 
eat five large larvse of Eurymus during a 
single day, and both the writer and Mr. T. 
Scott Wilson counted dozens of pupal cases 
with the contents eaten out (fig. IT) and 
many times with the Heliothis larva still 
feeding upon and devouring the pupae. Mr. 
Wilson, on July 15, 1913, remarked in his 
field notes that "Heliothis was observed in 
great numbers feeding upon Eurymus pupse, 
and in a few instances on Eurymus larvse. 
The Heliothis makes a hole in the side of 
the pupa, through which he puts his head 
and eats out the contents of the pupa." The writer has observed the 
end of the abdomen eaten off the pupa ; again, an opening would be 
made on the side, often the entire side being destroyed. 
1 Mallocb, J. R. The insects of the dipterous family Phoridae in the United States 
National Museum. Proc. U. S. Nat. Mus., v. 43, p. 459-460, 1912. "Aphiochceta perdita, 
new species," p. 459. 
2 This cannibalistic habit has also been observed in Texas by Quaintance and Brues. 
(U. S. Dept. Agr., Bur. Ent., Bui. 50, p. 79-80, 1905.) 
Pig. 17— Chrysalis of alfalfa 
caterpillar that has been 
eaten out by a bollworm. 
Enlarged about two diam- 
eters. (Original.) 
