504 
Ohsei'vations on the various Insects 
They were in abundance in a wheat-stack in Aprils and destroyed 
many acres of vT/e. 
Another species attacked the icheat-Jields last May. 
The larvce entered two inches beneath the surface, destroying 
the internal stalk. 
Other fields of wheat, sown in February and 3Iarch, were sub- 
ject to the same disease. 
These maggots produced in July a new species of fly, the 
Oscinis vastator. 
This, from its operations, appeared to be the most destructive of 
the species. 
They are kept in check by parasites. 
One, a kind of Ichneumon, named Ca^linius niger, feeds in the 
body of the maggots, and is frequently very abundant. 
Another, called Pteromalus micans, lives in the maggots also, 
and destroys them before they change to pupae. 
A third parasite, the Sigalphus caudatus, was bred from the 
pupae of Oscinis vastator. 
It is said to deposit its eggs in those of the Oscinis. 
Dr. Herpin recommends pullitig uj) and burning the infested 
plants, which may first be done when weeding is going on, and 
subsequently two or three weeks before harvest, when their size 
and colour readily distinguish them. 
Rotation of crops one of the best means of keeping free from 
noxious insects. 
Over-cropped land refuses to bear, perhaps as much from dis- 
eases caused by an excessive increase of insects in the soil as from 
exhaustion. 
Soot, and sand saturated with gas-water, sown over a field, 
might keep off the Cklorops. 
It is not improbable that some species of Cklorops breed in the 
stems of grasses. 
There are two broods of the maggots in a year, the first 
living in the spring, the latter through the winter, in some 
instances. 
The Jirst brood destroys the ear, the second the central shoot, 
alter which lateral shoots are sometimes matured. 
It is doubtful if the species of Oscinis produce two broods 
annually. 
The O. vastator is by far the most formidable enemy. 
Is it possible to attract the Jlics by white painted bcrards or 
poisonous liquids? 
Dusting the young corn with soot or lime would drive away the 
flies. 
Strong liquid mamires would annoy those broods which reside 
in the young corn-plants. 
