9374 Insects. 
Last autumn, in the vicinity of Quebec, the ravages of these larve 
were very great. Large plots and even fields of cabbages, cauli- 
flowers, &c., were completely destroyed, the caterpillars only rejecting 
the strong supporting ribs of the leaves. Serious loss was thus 
occasioned to market gardeners and others. One informed me that 
he had sustained a loss of more than 200 dollars by their depredations ; 
another that nearly the whole of his crop of cabbages was destroyed, 
the small portion saved requiring to be carefully washed before being 
sent to market. A gentleman also told me that they had not only 
eaten up his garden produce, but had demolished a bed of mignionette, 
even to the stalks. 
Nature has provided more than one means of checking the increase 
of the species. The chrysalis is attacked by a parasite (probably one 
of the Ichneumonide), as several collected by me this spring gave 
evidence. Large numbers of the pupz are also killed by the frost, 
where they have been placed in exposed situations, and thus the spring 
brood of butterflies is materially lessened. I noticed a singular cir- 
cumstance connected with these winter pupae. Living chrysalids, 
brought into the warm house from the cold outside, invariably shrivelled 
and died in a few days. Out of many that I gathered during last winter 
not one produced a butterfly. 
Last year the species was exceedingly abundant in the neighbour- 
hood of Quebec, flying by hundreds over the fields and gardens, and 
even in the most crowded parts of the city; and this season it pro- 
mises to be equally numerous. Early in March, the butterflies began 
to appear in houses, from pupz which had been suspended on the 
walls during the previous autumn. On the 6th of April, at Laval, about 
fifteen miles from Quebec, several specimens were taken in the open 
air, and on the 26th of May I counted more than fifty individuals, 
met with on about a mile of road within a short distance of the city. 
Considering their great abundance within their present habitat, and 
their prospective dissemination over the province, it is desirable that 
information respecting the appearance and habits of these insects 
should be given to the public, and means devised for their destruction. 
Farmers and gardeners should kill every caterpillar on their turnips, 
cabbages, &c., and be provided with nets to capture the perfect insects. 
The chrysalids should also be sought for on fences during the fall and 
winter, and destroyed. Unless these precautions be taken, the injury 
caused by this butterfly to the green crops in Canada may become 
very serious.* 
* Fyrom ‘The Canadian Naturalist,’ New Series, Vol. i. No. 4, p. 258. 
