PEST OF WHEAT, BYE, BARLEY, ETC. 25 
FOOD PLANTS, 
The question of the food plants of the Hessian fly presents a par- 
ticularly important one. for the possibility of its survival in a district 
where its normal food plants are not grown during one or two ye 
or of its living for one or two broods on grasses, so as to adapt itself 
better to crop conditions of cereals, all depend on whether it can exist 
on other than its principal known host plants. 
From early times the Hessian fly has been recognized as a pest of 
wheat, rye. and barley, and most of the early literature considered it 
simply as a pest of these crops. Some years sinee. however, the point 
was made that it could live on various grass plants, and some observa- 
tions by careful observers tended to support such a view. 
The following extracts from reports on this point will show the 
nature of the testimony submitted: 
The Hessian fly attacking grasses in California. — According to Lindemann. the He— 
sian fly has been found upon Phleum pratense and Agropyrnm repens in Russia, but 
up to the present year it had not heeu recorded as occurring in this country upon 
any wild grasses. 
"We are'in position now, however, to add four grasses to the list of its food pbrits 
in the United States. In 1887 Mr. Koehele sent us from Alameda, CaL, specimens of 
Elymu8 americanus and of a species of Agrostis which bore pnparia supposed to he 
those of this insect. The adults were not reared, however, and tin- question remained 
unsettled. On page 71 of the current volume we published, under the head of 
"California notes." a letter from Mr. Koehele. in which he mentioned finding Hessian 
fly pnparia in a grass in the Santa Cruz Mountains. This fact was called in <|".es- 
tion by Mr. James Fletcher, and we wrote Mr. Koehele for specimens and received 
from him Bromus ciUatus and a species of Agropyrum. both carrying pnparia. These 
were very much like the normal pnparia of the Hessian lly. but were smoother and 
more plump, showing little trace of the longitudinal ridges. Plies were obtained 
from these, and others also obtained from the grasses were sent on by Mr. Koehele; 
and. alter comparing these very carefully with specimens from wheat from different 
parts of the country, we find they are not to be separated, although from the speci- 
mens first received a variation in the number of the antenna] joints raised some 
doubts. We find, however, alter the examination of nearly 100 specimens of individ- 
uals reared from wheat from various sections that the joints of the antennae in the 
male range from 16 to 20 and in the female from lii to l!'. * 
On the other hand, we have, aside from all the early history of the 
pest, a number of positive records which strongly confirm the view 
that the insect never occurs normally or survives on other plants than 
wheat, barley, and rye, which arc in closely related genera. 
In 1890 Professor Forbes undertook to prove experimentally whether 
the Hessian fly could develop on other plants than its usual hosts, and 
to this end introduced flies into cages with timothy, redtop [Agrostis 
vulgaris), bine grass (Poa pratensis .orchard grass Dactylis glomerata . 
and foxtail (Setaria), in all cases without result, though in some « 
active adults had every opportunity to deposit eggs. While Professor 
Forbes gives this result only negative value, it is certain that it gives 
no support to the idea of a variety of food plants, and. taken with the 
• Insect Life, Vol, III, p. 306. 
