36 
brooded; that the eggs are laid by the adult upon the young wheat 
in autumn; that the larvae hatch and hibernate within the stem, 
pupating in May and emerging late in that month and early in June! 1 
They leave the stem, in fact, at about the time the young Isosom j 
tritici commences its attack upon the wheat, and consequently these 
two species, although specifically clearly distinguished, nevertheless ! 
alternate like two broods of the same form. 
Concerning the distribution of this species, it can, at present, only 
be said that it occurs in Western and Southern Illinois and in parts | 
of Indiana adjacent. As this insect inhabits the wheat only during 
the period of the growth of the plant, escaping before the grain is [ 
harvested, and passing the interval a3 a free imago, it is difficult, 
to see how its injuries may be prevented, unless, indeed, late sow- 
ing, as practiced for the Hessian fly, may be found to affect this 
straw-worm also. 
2. The Lesser Wheat-Straw Worm. 
(.Isosoma tritici, Riley.) 
. 
Order TIymenoptera. Family Chalcidid.e. 
(Plate I, Fig. 5.) 
Observations made during the present season add one or two 
points of interest to the life history of this destructive species. The 
period when it begins its injuries has heretofore been a matter of 
inference, but it was this summer found by Mr. Garrnan at work in 
the wheat as early as June 5, many of the larvae being at this time 
only a millimetre in length, and evidently but recently hatched. 
The exact character of the injury produced by these young larvae is 
well illustrated by the accompanying figure, exhibiting the cavity 
from which a very small straw worm was removed. 
The parasitism of Eupelmus allyni upon this species and Isosoma 
hordei has been placed beyond question by recent observations of 
Prof. French, reported in the Canadian Entomologist for July, 1884, 
pages 123 and 124. As evidence on this point, he says: 
U A single joint of rye containing several galls formed by Isosoma 
hordei was put into a bottle and corked up, so that no insects could 
get out or in. In due course of time a specimen of E. allynii was 
found in the bottle, and the hole from which it had gnawed its way 
out of one of the galls was plainly to be seen. Afterward the other 
galls gave forth I. hordei. In this case there could be no question 
but that the specimen of E. allynii came from the gall made by 
I. hordei. If no hordei had hatched from the other galls, this would 
have been evident, for the galis made by this species are too char¬ 
acteristic to be mistaken by any one at all familiar with their "work. 
I have bred quite a number of this species from the inside of the 
stems of wheat; and in all cases they came from the cavities in¬ 
side the stalk that had been gnawed by Isosoma tritici. Though 
this species of Isosoma makes no gall, its manner of eating the 
