My first visit to this field was made August 4, at which time 
two strips had been sowed, the wheat on the first being four 
inches high and that on the second just coming up. Several hours’ 
search in the former plot gave no trace of the fly in any condition. 
A large number of plants sent to the office were carefully scruti¬ 
nized, especially for the egg upon the leaf, but likewise without 
success. This wheat was badly damaged (as already said) by the 
third brood of the wheat bulb worm (Meromyza americana), one 
half to two thirds of the plants having been already killed by this 
insect. On the 20th August these plots were visited by my assist¬ 
ant, Prof. Garman, and the volunteer wheat mentioned above was 
also searched, but equally without result. The wheat was now al¬ 
most exterminated by the bulb worm upon the first two plots, and 
these were thereafter left out of the account. Only small patches 
occurred where the plants were possibly thick enough to attract 
the imago. 
On the 4th September I spent several hours in the volunteer 
ivheat (which, it will be remembered, sprang up about the 20th 
July), searching in every imaginable way for eggs and larvae, but 
finding nothing of the Hessian fly. Three hundred and seventeen 
plants selected from those least flourishing were sent to the office 
and there carefully searched, magnifier in hand, for both eggs and 
larvae, but not one of either was detected. 
Again, September 18, this field was thoroughly investigated, 
about two hours being spent by myself and several volunteer assist¬ 
ants in closely examining leaves and stalks and tearing the plants 
in pieces. Although several other dipterous larvae and pupae were 
discovered, some of them possibly injurious to the plant, not a 
trace of the Hessian fly was seen. The owner assured me, how¬ 
ever, that he had the day before happened upon two puparia 
which he w r as certain were those of the species in question. Ten 
days later (on the 28th Sept.) I received from Mr. Young a small 
vial of alcohol, containing larvae and puparia of the Hessian fly, 
the latter freshly formed, the former from half to full grown. 
These were taken by Mr. Y r oung from the volunteer wheat, and 
were the earliest positive indications found that this wheat had 
been infested. As about three weeks* is required for the growth 
of the larva from the egg, the latter was probably laid for the 
larger larvae not long after September 5. 
The difficulty of finding in fields of wheat a few scattered ex¬ 
amples of objects so minute as the egg of the Hessian fly, explains 
our failure to detect it at the time. Indeed it was not until the 
individual plants began evidently to suffer that it became at all 
easy to find even larvae in the field. 
October 11, I again visited Billett Station, and found numbers 
of larvae and puparia of the fly, about one third to one half of the 
stalks being infested, and those containing the pupuria all dead. 
Probably a tenth of the specimens obtained were puparia, seven 
I --- 
* See next page. 
