(Culicida) are confounded under the common names of gnat and musquito, as if there were only one or two species; whereas Mr. Stephens has enumerated twenty-two species of the genera Culex and Anopheles, found in Britain alone*; and hence it is probable, the foreign mosquitoes are also of several species, though to common observers they do not appear to differ from the common gnat (Culex pipiens).

Sucker of the cleg (Hamatopota pluvialis): a, cleg, natural size; b, part of the head magnified; c, magnified still more, showing the facetted eye, the short antennæ, and the sucker unsheathed; d, the lancets, &c. of the sucker, separated to show their structure.

Catalogue, ii. p. 232, 233; and Zool. Journ. i. 452, iii. 500.

The considerable difference of form must prevent the most indifferent observer from confounding gnats with the gad-flies (Tabanide). Their instrument of annoyance is also very different from that of the gnat, being much larger, more formidable, and not less skilfully adapted to its office. The figures will exhibit the difference at a glance.

Réaumur took advantage of his carriage being stopped in a narrow pass by some oxen, which were surrounded by gad-flies, to study the operation of one which alighted on his hand, by means of a magnifying-glass of considerable power. It gave him considerable pain, pierced a deep hole in his skin larger than the prick of a pin, and he afterwards found in the body of the insect seven or eight large drops of blood *. Lambert, in speaking of some fly of this order, says, "they are so very small as to be hardly perceptible in their attacks; and your forehead will be streaming with blood before you are sensible of being amongst them." Again he says, "I have sat down to write, and have been obliged to throw away my pen in consequence of their irritating bite, which has obliged me every moment to raise my hand to my eyes, nose, mouth, and ears, in constant succession †." It is very probable that our author here means a fly of a different family (Stomoxydæ, MEIGEN) from the preceding. One of these is so like the common housefly (Musca domestica), as to be readily mistaken for it, though the house-fly has no organs fitted for penetrating the skin. Kirby says, (Stomoxys calcitrans, FABR.), I incessantly interrupts our studies showery weather, making us even cattle by its attacks on our legs; and if we drive it away ever so often, it will return again and again to Trav. through Canada, i. 126, 127.

*Mém. iv. 230.

this little pest speak feelingly, and comfort in stamp like the

the charge, and even contrives to make a comfortable meal through our silk or cotton stockings, by means of its horny, sharp-pointed weapon*." But this little phlebotomist is a solitary, not a social insect, like the house-fly, and seldom visits our apartments except when driven thither by bad weathert.

We have more than once alluded to the extraordinary change which takes place in the stomach and intestines of insects, when they pass from the infant to the perfect state; and have now to remark, that a similar change takes place in the organs of the mouth. In caterpillars, for example, the mouth is furnished with strong cutting mandibles, for feeding upon hard substances; while the moth or the butterfly, into which these are transformed, has only a tubular sucker, for absorbing the honey of flowers. But this change in the feeding organs, though so strikingly obvious, M. Savigny is not disposed to admit, proceeding upon the principle recently adopted in the French school, from hints found in Aristotle, Willis, and De Geer, which finds analogies and similarities in the members of animals the most remote from each other in structure and functions. The shell of the lobster, for example, is thus fancied to correspond to the bones of quadrupeds, not only in general, but in all its various pieces; and the breast-fins of the whale are imagined to be analogies of the hands in man; the change being traced in successive gradations, from the ape, through the otter, seal, walrus, manati, and dugong, to the whale §. It may be well to hear what Savigny himself says on the subject immediately before us.

*Intr. i. 49-112.

+ J. R. Aristotle, Hist. Anim. iv.; Willis, De Anima Brutorum, p. 11; De Geer, Mem. ii, 2; Geoff. St. Hilaire, Mem. de l'Institute Franç.

§ Harwood, Brande's Journ.

Speaking of the suckers of butterflies, he remarks, that "the semblance is taken for the reality; for butterflies, in the same manner as their caterpillars, and as beetles, bees, and all eating insects (broyeurs), have two lips, one upper and one under; two mandibles; and two jaws (machoires.) This fact, though opposed to received opinions, is not the less certain. These parts, indeed, occupy their ordinary place. It is true they are so much shrunk and so much modified in their form and in their relative proportions, that it is not astonishing they have been misconconceived by excellent observers. How different soever these parts may appear from ordinary man

A, Profile of the head, with the sucker unrolled. B, Upper lip and man dibles. C, Jaw and part of the sucker. D, Labial palpi. E, Portion of the sucker (A), showing the three tubes of which it is composed; viewed from above. F, The same parts, viewed from beneath.

Should

dibles, it is impossible to refuse the name. an objection be raised from their substance, I have already said that they are horny, and although hollow within, they are more solid than the mandibles of certain beetles. Should their configuration be objected to, the conical form which they affect, is that of all mandibles; they have one point and one base distinct; and as they are fringed on their internal margin with numerous hairs, the mandibles of many bees and beetles are similarly fringed. Should we object to their mobility; it is answered, that though they are sometimes as it were glued (soudées), they are also sometimes articulated and distinctly moveable. Is their minuteness objected to? The day-flies (Ephemeride) and water-flies (Phryganida) have mandibles smaller and more imperfect still, and yet nobody doubts that the latter ought to be placed among insects with jaws *"

From this extract our readers may learn the general principles of this doctrine, which is carried into minute details, derived from the very extensive and profound knowledge of the author. Although we may incline to believe these opinions more fanciful than just, and while we object to the hypothetical names given by M. Savigny, we readily acknowledge the very extraordinary accuracy of the dissections and figures which he has supplied in illustration.

Mémoires sur les Anim. sans Vertèbres, i. 5.

T