Prof. Riley, indeed, remarks in the first report: “There is every 
3ason to believe, however, that Nature has her own means of keep- 
tg these hies within due bounds, for they are known to be preyed 
pon by parasitic Ichneumon flies in Europe, and I noticed many 
ies of this last description, of polished hues and active movements, 
eftly darting through and resting upon the wheat plants of the 
elds infested with the Meromyza.” 
Mr. Lintner makes no mention of parasites in his article on this 
pecies, and the first discovery of them was made by myself in 
pril of this year, among specimens from the field at Cuba already 
•equently referred to, which I was rearing to the perfect stage, 
ideed, the first pupa-case of Meromyza which I opened (April 25), 
mtained a well formed pupa of a hymenopterous parasite (Plate 
[, Fig. 2), and on the 6th of May-two days after the adult Mero- 
lyzas began to appear,—two mature specimens of this parasite oc- 
urred in our breeding cages. These were evidently of the genus 
oelinius, but of a species of which I have not been able to find 
ny description, and which is probably new. 
The abundance of these^ parasites in this field may be inferred 
X)m the fact that out of fifty-five larvae obtained here, only twenty- 
ne developed the fly, and the thirty-four remaining all gave origin 
) the Coelinius, which continued to emerge from May 6 to May 
9. Sweepings of these infested fields in April shielded none of this 
pecies, and there can be no doubt that the eggs are deposited 
ithin the bodies of the larvae in autumn. 
Whether this same parasite infests likewise the summer brood of 
irvae, we are unable to say; but it seems extremely doubtful if it 
i at that time as destructive to the host species as when the latter 
> freely exposed to its attack among the leaves of the young wheat, 
k probably partly on this account that the midsummer brood 
3ems much less numerous and destructive than the autumnal. The 
ttack of the parasite does not arrest the growth of the larva, and 
msequently cannot prevent the injury to the plant; but, on the 
mtrary, the infested worm goes on eating until it is ready to pu- 
ate, and, indeed, actually transforms. The prevalence of the para¬ 
de must, however, greatly diminish the number of the perfect 
lsects appearing in spring, and consequently of the midsummer 
irvas. On the other hand, the relative immunity of the latter from 
arasitism will not increase their own mischief in the field, but will 
aye the effect to increase the number of the autumnal brood. 
In short, as the parasitism takes effect only on the damage done 
| y the generation succeeding that parasitized, and as it seems to 
reveu Jchiefly among the winter brood of the larvae, it is the mid- 
immer brood whose injuries are lessened by it,—from which it fol- 
>ws that the autumnal and winter brood will ordinarily be found 
le more mischievous of the two. There is, however, one circum- 
jance to modify this conclusion. The autumnal damage, and even 
iat of spring, is done at a time when the wheat plant is some- 
mes able, by tillering, to replace in part the stalks killed by the 
orms, while that of midsummer is irremediable. I add description 
’ad figuremf this parasite. 
I *» 
