152 
Observations on the various Insects 
several successive years, when they disappeared ; which is attri- 
buted, by KoUar,* to the mowing down the infested oats whilst 
the insects were in the larva state. 
The economy of this species bears a great resemblance to the 
Hessian fly, which, however, does not enter the earth to undergo 
its metamorphoses ; and it is very remarkable that three species, 
so closely allied to each other, should vary so considerably in their 
habits. With regard to the Hessian fly, even if its presence could 
be asceiiained in the early stages, it does not seem possible to de- 
vise any means of destroying the eggs or young larvae, unless feed- 
ing off" the blade with sheep would elFect the object : and when 
their progress is detected by their mischievous works, at a more 
advanced period, nothing, I apprehend, but sacrificing the crop 
would arrest them. It appears, therefore, to be an evil to which 
we must occasionally submit ; but to guard against its immediate 
recurrence it will only be necessary to collect and bum the stubble 
after the corn is reaped, by which means the larvae and pupae that 
are concealed at the base of the stalk will of course be destroyed. 
Kollar recommends agriculturists, as a means of prevention, to 
refrain from sowing wheat the following year : but whether such 
a sj'stem could be adopted in North America I am not prepared 
to say. 
Summary of the foregoing Report. 
Larvce of a saw-fly called Cephus pygmmis destroy the rye by 
injuring the straw : they live through the winter, change to pupae 
in March, and the flies hatch in April. 
The female fly pierces and deposits her eggs in the rye-straw, 
or immediately below the ear: the larva; live in the interior, 
piercing the knots, and about harvest time cut through the stem 
close to the ground, descend into the remaining stubble, and 
change to pupa;. 
This insect is detected by the ears becoming upright and appa- 
rently ripe in the infested plants, whilst the remainder of the crop 
is green. 
K field thus affected sometimes looks as if it had been traversed 
hy sportsmen and animals. 
This saw-Jiy is very abundant in cornfields, particularly 
amongst barley, in June and July, in many parts of England. 
It also infests the wheat-crops. 
On the western coast of France this insect has caused great 
ravages ; and similar losses have been sustained in Africa. 
The ears, both of wheat and rye, become steril from the attacks 
the Cephus. 
* Nalurgeschichte der schaedlichen Insecten, p. 136. 
