a new country,-an instance which, when the evidence is considered, must be regarded as the most conclusive on record.

The identity of the English and Canadian species is thus proved by the exact similarity of the two insects in all their stages. That the imagines are alike, in both sexes, I have on the authority of the gentlemen above named; for in Quebec I could have no opportunity of comparing specimens taken in both countries. It is singular, too, that a curious variety of the male is common to both: in Canada, however, (perhaps from the effect of a different climate) it is more frequently met with than in England. Two males of a bright canary color, but with the usual markings of the species, were captured here last summer-one by Mr. Couper, the other by me; and this season I have already seen several similar individuals. On referring to a valuable work in the library of Parliament, (Curtis's Farm Insects,) I was gratified to find that the author mentions having in his collection a male P. rapa, "taken near Oldham, in Lancashire, which has all the wings of a bright yellow color." As to the pupa, in size, color and markings, it exactly agrees with engravings and descriptions of the English chrysalis, and also in its usual place of deposition, &c. The last link in the chain is furnished by the similarity of the caterpillar, which also agrees with the best English descriptions. I took several of these larvæ from cabbage-plants in hotbeds on the 8th of June, and have reared four of them to maturity. When about half-grown, they began to exhibit the characteristic markings of the species, these markings becoming more decided as they increased in size.

That this insect is not native to Canada, is certain from two interesting circumstances connected with its history. A limit can be set to its existence in Canada; and the place where it first appeared can be specified. Until within a few years, the butterfly was unknown in this country. No description of it is found in Kirby's "Fauna Boreali Americana"; nor in the "Canadian Naturalist," by Gosse, who visited Quebec, and collected here about 1839. The "Synopsis" of the Smithsonian Institution is also wanting in this respect; and I have carefully examined the volumes of our magazine of natural history, (the "Canadian Naturalist," Montreal) without finding any notice of the species. This periodical contains two lists of lepidoptera colected in Lower Canada; one by Mr. R. Bell, Jun., of butterflies taken on the Lower St. Lawrence; the other by Mr. D'Urban, of those found in the vicinity of Montreal in 1857-8-9. The only Pieris

mentioned in these lists is P. oleracea, a species which may be distinguished at a glance from P. rape, the markings being altogether different. Mr. Couper captured a specimen of P. rapa within the city limits of Quebec, about five years ago, but did not investigate the subject, though considering the insect a rare one, his special study being coleoptera. This is the earliest notice of the butterfly in Canada; and it evidently points out Quebec as the locality of introduction, and fixes the period at about seven or eight years ago.

With respect to the means by which it has been brought into the country, some plausible conjectures may be advanced. Of course the introduction took place during the season of navigation. The turnip, cabbage, and other kindred vegetables, constitute the principal food plants of the insect; and, adhering to one of these, it must have been carried across the ocean, either in the egg, larva, or chrysalis,-the last being the most unlikely, as the larva always forsakes its food-plant, and becomes a pupa in some sheltered situation, usually under the coping of a wall, &c. The eggs are laid on the under side of cabbage and turnip leaves, where the larva, on emerging, find themselves in close proximity to their food. Perhaps the vegetable refuse thrown from one of our ocean steamers on her arrival, has contained a few eggs or larvæ, which under these unfavourable circumstances, have retained their vitality; and from these have sprung the imagines destined to become the parents of the species in Canada.

The habitat of the insect is still very limited. After making enquiry, I do not think that it has extended more than forty miles from Quebec as a centre, so that a circle of eighty miles diameter would include the present habitat. This may seem great progress during the short period of its naturalization, but, considering the fecundity and habits of the species, it is not surprising.

There is some importance connected with the introduction of this butterfly, apart from the scientific interest of the subject to entomologists. Hitherto, Lower Canada has possessed but one species of the genus Pieris (P. oleracea, Harris; Pontia casta, Kirby,) and this species so insignificant in numbers, at least in the Quebec region, that its depredations have passed unnoticed. The new importation, however, must be regarded in a different light. As the insect is now permanently settled in the country, is very prolific, and the larvæ extremely voracious, we may anticipate its becoming a great pest to farmers and gardeners, not only where it is now found, but ultimately in the whole of Canada, and

parts of the United States. And that it will in the course of time spread over these regions, admits of no doubt. The food-plants of the species are cultivated in every part of the country, and besides, the insect has the power of accommodating itself to altered circumstances. Mr. Curtis, in the work before mentioned, states that the caterpillars have been found feeding on the willow, and on mignionette, nasturtiums, &c. It is therefore probable that its progress westward will not be impeded by the scarcity of its favorite food in certain localities, but that it will overcome all difficulties of this nature by resorting to other plants, not confining itself to the cruciferæ.

Last autumn, in the vicinity of Quebec, the ravages of these larvæ were very great. Large plots, and even fields of cabbages, cauliflowers, &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 two hundred 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 Ichneumonidae) as several collected by me this spring gave evidence. Large numbers of the pupa 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 circumstance connected with these winter pupa. Living chrysalids, brought into the warm house from the cold outside, invariably shrivelled and dried 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 neighborhood of Quebec, flying by hundreds over the fields and gardens, and even in the most crowded parts of the city; and this season it promises to be equally numerous. Early in March, the butterflies began to appear in houses, from pupa which had been suspended on the walls during the previous autumn. On the 6th April, at Laval, about fifteen miles from Quebec, several specimens were taken in the open air; and on the 26th 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 the 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.

The following is a description of the insect:

Male-wings white, (or light yellow) with one blackish spot on the fore wings above, and two beneath, a black band on the apex on the upper side, extending a short distance along the adjacent margins, a black dash on the fore edge of the hind wings, which are beneath of a pale yellow sprinkled with black. Body black, antennæ annulated with black and white. Female has two black

ish spots on upper side of anterior wings.

inches.

Expands about two

Chrysalis-Pale green, speckled with black, suspended horizontally by the tail and a thread across the middle.

Caterpillar-About 1 inches long when full grown, green finely dotted with black, a yellow stripe along the back, and a row of yellow spots along each side in a line with the spiracles.

The caterpillars reared by me were about one-twelfth of an inch long when I procured them, and attained their full size in eleven days. On the 19th June they became pupæ, and seven days after the perfect insects appeared. The butterfly therefore passes through all its changes in less than a month. Three or four broods are produced during the season.

(Read before the Quebec Branch, Entomological Society of Canada. 7th July, 1864.)

SYNOPSIS OF CANADIAN FERNS AND FILICOID

PLANTS.

BY GEORGE LAWSON, PH.D., LL.D.

The following Synopsis embraces a concise statement of what is known respecting Canadian ferns and filicoid plants. Imperfect as it is, I trust that it will prove useful to botanists and fern

fanciers, and stimulate to renewed diligence in investigation. The whole number of species enumerated is seventy-four. Of these eleven are doubtful. Farther investigation will probably lead to the elimination of several of the doubtful species, which are retained for the present with a view to promote inquiry; but a few additional species, as yet unknown within the boundaries of Canada, may be discovered. The above number may be regarded, then, as a fair estimate-perhaps slightly in excess-of the actual number of ferns and filicoid plants existing in Canada. The number certainly known to exist, after deducting the species of doubtful occurrence, is sixty-three.

The number of species described in Professor Asa Gray's exhaustive Manual, as actually known to inhabit the northern United States, that is to say, the country lying to the south of the St. Lawrence River and Great Lakes, stretching to and including Virginia and Kentucky in the south, and extending westward to the Mississippi River, is seventy-five. This number does not include any doubtful species.

The number described in Dr. Chapman's Flora, as inhabiting the Southern States, that is, all the states south of Virginia and Kentucky and east of the Mississippi, is sixty-nine.*

From these statements it will be seen that we have our due share of ferns in Canada.

The whole number of ferns in all the American States, and the British North American Provinces, is estimated, in a recent letter from Mr. Eaton, as probably over 100.

In the British Islands there are about 60 ferns and filicoid plants. In islands of warmer regions the number is greatly increased. Thus Mr. Eaton's enumeration of the true ferns collected by Wright, Scott, and Hayes, in Cuba, embraces 357 species. The proportions of ferns to phanerogamous plants in the floras of different countries are thus indicated by Professor Balfour, in the Class-Book of Botany, page 998, §1604:-" In the low plains of the great continents, within the tropics, ferns are to phanerogamous plants as 1 to 20; on the mountainous parts of the great continents, in the same latitudes, as 1 to 8,or 1 to 6; in Congo as 1 to 27; in New Holland as 1 to 26. In small islands, dispersed over a wide ocean, the proportion of ferns increases; thus while in

* Mr. D. C. Eaton, M.A., is author of that portion of Dr. Chapman's Flora which relates to the ferns.