DEVELOPMENT. 23 
The weather conditions of this year increased the difficulty of fighting the Hessian 
fly in high altitudes. The wheat fields, namely, which were sown in June for the 
purpose of attracting the Hessian fly, could not fulfill their mission, because the fly 
at this time had not yet emerged. 
The recommendation made by several entomologists to delay the sowing until 
August could not protect the crop from the Hessian fly, because it emerged just at 
this time. The plowing under of the stubble after harvest proved itself the only 
method applicable in this season to accomplish the destruction of the puparia con- 
tained therein. Although in this wise the weather conditions of the past summer 
greatly increased the difficulty of combating the Hessian fly, they proved them- 
selves, on the other hand, to be unfavorable for the life of the fly itself. Simulta- 
neously, with the retardation which the puparia of the Hessian fly experienced under 
the influence of the dry and hot weather, there took place the rapid increase df its 
enemies — parasites from the subfamily Pteromalime, which under these unfavorable 
conditions overrun the Hessian fly in great numbers and destroyed 50 to 70 per cent 
of its puparia. 
A letter from Mr. John G. Andras, of Manchester, 111., to Dr. Howard 
bears so directly on this point that it is reproduced here, and, although 
it will be seen that it is in large part covered by observations already 
cited, its corroborative value will justify its introduction : 
On examining some fields of spring wheat that were destroyed by what farmers 
thought to be chinch bugs, I found the Hessian fly was the real cause. The spring 
wheat was sown on killed-out winter wheat early sown in September, 1896. The 
spring wheat sown early in March, 1897; the killing out of the fall was complete, 
hardly a single plant left. 
By the surroundings it seems the Hessian fly in the puparium stage was not 
destroyed, but the warm days of the latter part of April brought them to the mature 
form, and egg laying began, the larva going below the ground one-half to 1 inch 
deep. The puparium cases are abundant on, or in, the extreme lower clasping base 
of the almost killed plant (spring wheat), and the mature fly is laying eggs on the 
blades at the present time. This cycle seems to point to a more rapid maturity than 
1 supposed this insect went through. From the middle of March to the 28th of May 
has completed the period from egg to maturity, and with the present egg-laying 
would give the second brood by harvest. The usual damages here have been from 
the eggs laid iu early fall (September), the perfect insert in May laying eggs about 
2 inches from the ground, which matured in .June, this last being the injurious brood. 
But this spring-wheat broou has completed one brood at present (May 29 | and would 
complete the second brood by harvest (middle of July is our spring-wheat harvest), 
which is making them double brooded by end of our harvest season. 
I note in the American Entomologist, page IIS. volume :5 (Sec. Ser., vol. 1 that 
''spring wheat can rear but one brood," but where the puparium is left in thegrouud 
from the winter wheat being killed out by freezing, they will raise two broods by 
spring-wheat harvest time in this locality. 
My own observations in this direction have been devoted more par- 
ticularly to the spring-wheat regions of the Northwest, as here the 
occurrence of the insect presents some interesting problems. 
The material I obtained in L896 produced only parasites, and these 
in considerable numbers, so that only negative evidence was secured as 
to the amount of retardation resulting from conditions prevailing in 
this region. 
Prof. O. Lugger reports almost identical results in Minnesota. After 
mentioning its occurrence in the central western part of that State, 
from Browns Valley to the .Mississippi River at St. Cloud, and e>ri- 
