the beards, and he says he saw great numbers of them on the ground." From these observations, and from remarks to the same effect, made to me by intelligent farmers, it appears that the descent of the insects is facilitated by falling rain and heavy dews. Having reached the ground, the maggots soon burrow under the surface, sometimes to the depth of about an inch, those of them that have not already moulted casting their skins before entering the earth. Here they remain, without further change, through the following winter. During the month of May, I have seen specimens still in the larva form, in the earth wherein they had been kept during the winter. It is not usually till June that they are transformed to pupæ. This change is ef fected without another moulting of the skin; not the slightest vestige of the larva-skin being found in the earth in which some of these insects had undergone their transformations. Moreover, the pupa is entirely naked, not being enclosed either in a cocoon or in the puparium formed of this outer skin of the larva, and it has its limbs and wings free or unconfined. The pupa state lasts but a short time, a week or two at most, and probably, in many cases, only a few days. Under the most favorable circumstances, the pupa works its way to the surface, before liberating the included fly; and when the insect has taken wing, its empty pupa-skin will be seen sticking out of the ground. In other cases, the fly issues from its pupaskin in the earth, and comes to the surface with flabby wings, which soon expand and dry on exposure to the air. This last change occurs mostly during the months of June and July, when great numbers of the flies have been seen, apparently coming from the ground, in fields where grain was raised the year before. Some persons have stated that the insects are transformed to flies in the ears of the grain, having probably mistaken the cast-skins of the maggots found therein for the shells of the chrysalis or pupa. Several cases of the efficacy of fumigation in preventing the depredations of these insects are recorded in our agricul "New England Farmer," Vol. XVI., p. 61. tural papers. For this purpose brimstone has been used, in the proportion of one pound to every bushel of seed sown. Strips of woollen cloth, dipped in melted brimstone, and fastened to sticks in different parts of the field, and particularly on the windward side, are set on fire, for several evenings in succession, at the time when the grain is in blossom; the smoke and fumes thus penetrate the standing grain, and prove very offensive or destructive to the flies, which are laying their eggs. A thick smoke from heaps of burning weeds, sprinkled with brimstone, around the sides of the field, has also been recommended. Lime or ashes, strown over the grain when in blossom, has, in some cases, appeared to protect the crop; and the Rev. Henry Colman, the Commissioner for the Agricultural Survey of Massachusetts, says that this preventive, if not infallible, may be relied on with strong confidence.† For every acre of grain, from one peck to a bushel of newly slacked lime or of good wood ashes will be required; and this should be scattered over the plants when they are wet with dew or rain. Two or three applications of it have sometimes been found necessary. Whether it be possible to destroy the maggots after they have left the grain, and have betaken themselves to their winter quarters, just below the surface of the ground, remains to be proved. Some persons have advised ploughing up the ground, soon after the grain is harvested, in order to kill the maggots, or to bury them so deeply that they could not make their escape when transformed to flies. I am inclined to think that deep ploughing will prove to be the best and most practicable remedy. Perhaps thoroughly liming the soil before it is ploughed, may contribute to the destruction of the insects. The chaff, dust, and refuse straw should be carefully examined, and, if found to contain any of the maggots, should be immediately burnt. It is stated that our crops may be saved from injury by sowing early in the autumn or late in the spring. By the first, it is supposed that the grain will become hard before many of the flies make their appearance; P. 136. * Among others, see "The Cultivator,” Vol. V., and by the latter, the plants will not come into blossom until the flies have disappeared. In those parts of New England where these insects have done the greatest injury, the cultivation of fall-sown or winter grain has been given up; and this, for some years to come, will be found the safest course. The proper time for sowing in the spring will vary with the latitude and elevation of the place, and the forwardness of the season. From numerous observations, made in this part of the country, it appears that grain sown after the fifteenth or twentieth of May generally escapes the ravages of these destructive insects. Late sowing has almost entirely banished the wheatflies from those parts of Vermont where they first appeared; and there is good reason to expect that these depredators will be completely starved out and exterminated, when the means above recommended have been generally adopted and persevered in, for several years in succession. In the introductory chapter a short account has already been given of the habits of the various kinds of gnats and flies, belonging to the principal families of this order. Besides the species that are injurious to vegetation, which have been now described, there still remain some of our native flies, that deserve a passing notice, on account of their size, or of peculiarities in their forms, structure, and habits, although few of them are to be included among the insects which are hurtful to plants. Among our long-legged gnats there is no one more singular in its appearance and graceful in its motions than the Ptychoptera clavipes, of Fabricius, or club-footed Ptychoptera. A new genus, called Bittacomorpha, on account of the fancied resemblance of this insect to the Neuropterous genus Bittacus, has lately been made for its reception, by Mr. Westwood.t This pretty gnat is of a black color, with a broad, white stripe on the face, a short, white line on the fore part of the thorax, and three broad, white rings on the legs. The sides of the thorax are silvery white, and the hind body is dusky brown, with a narrow white line on the edges of each of the rings. • Page 13. ↑ "Philosophical Magazine," Vol. VI., p. 281. Lond. 1835. The head is small, and almost hidden under the thick and hunched thorax; the antennæ are many-jointed, slender, and tapering; the hind body is long, narrow, and somewhat flattened; the legs are very slender next to the body, and increase in thickness towards the end, and the first joint of the feet is swollen, oblong oval, and very downy. The length of the body is about half an inch, and the wings expand nearly three quarters of an inch. It appears in July, and takes wing by day. As it flies slowly along, it seems almost to tread the air, balancing itself horizontally with its long legs, which are stretched out, like rays, from the sides of its body. The head is There are exceptions to almost all general rules. Thus we find, among Dipterous insects, some kinds that never have wings. One of these is the thick-legged snow-gnat, or Chionea valga. This singular insect looks more like a spider than a gnat. Its body is rather less than one fourth of an inch long, and is of a brownish yellow or nankin color. The legs are rather paler, and are covered with short hairs. small and hairy. The first two joints of the antennæ are thick, the others slender and tapering, and beset with hairs. Although the wings are wanting, there is a pale yellow poiser on each side of the hinder part of the thorax. The hindmost thighs are very thick, and somewhat bowed, in the males, which suggested the name of valga, or bow-legged, given to the insect in my "Catalogue." The body of the female ends with a sword-shaped borer, resembling that of a grasshopper. These wingless gnats live on the ground, and the females bore into it to lay their eggs. They are not common here. Mr. Gosse found considerable numbers of them in Canada, crawling on the snow, in pine woods, during the month of March.* Travellers and new settlers, in some parts of New England and Canada, are very much molested by a small gnat, called the black fly (Simulium molestum), swarms of which fill the air during the month of June. Every bite that they make draws blood, and is followed by an inflammation and swelling which last several days. These little tormentors are of a black color; * "Canadian Naturalist," p. 51. their wings are transparent; and their legs are short, and have a broad whitish ring around them. The length of their body rarely exceeds one tenth of an inch. They begin to appear in May, and continue about six weeks, after which they are no more seen. They are followed, however, by swarms of midges, or sand-flies (Simulium nocivum), called no-see-'em, by the Indians of Maine, on account of their minuteness. So small are they, that they would hardly be perceived, were it not for their wings, which are of a whitish color, mottled with black. Towards evening these winged atoms come forth, and creep under the clothes of the inhabitants, and by their bites produce an intolerable irritation, and a momentary smarting, compared* to that caused by sparks of fire. They do not draw blood, and no swelling follows their attacks. They are most troublesome during the months of July and August. The most common of our large gad-flies, or horse-flies, appears to be the Tabanus atratus, of Fabricius. It is of a black color, and the back is covered with a whitish bloom, like a plum. The eyes are very large, and almost meet on the top of the head; they are of a shining purple-black or bronzed black color, with a narrow jet black band across the middle, and a broad band of the same hue on the lower part. The body of this fly is seven eighths of an inch or more in length, and the wings expand nearly two inches. The Tabanus cinctus, of Fabricius, or orange-belted horse-fly, is not so common, and is rather smaller. It is also black, except the first three rings of the hind body, which are orange-colored. The most common of our smaller horse-flies is the Tabanus lineola, so named, by Fabricius, because it has a whitish line along the top of the hind body. Besides these flies, we have several more kinds of Tabanus, some of which do not appear to have been described. These blood-thirsty insects begin to appear towards the end of June, and continue through the summer, sorely tormenting both horses and cattle with their sharp bites. Their proboscis, though not usually very long, is armed with six stiff, and exceedingly sharp needles, wherewith they easily See Gosse's "Canadian Naturalist," p. 100. |