BLUE-BOTTLE BLUE-BREAST. 



533 



they are able to fly, have the same manners with 

 their parents, and at the season when these are 

 first on the wing-, some extensive commons have 

 appeared almost entirely in motion with our common 

 species *." 



Speaking of the migration of the blue-birds, Wil- 

 son observes, that " nothing is more common in 

 Pennsylvania than to see large Hocks of these birds, 

 in spring and fall, passing at considerable heights in 

 the air ; from the south in the former, and from the 

 north in the latter season. I have seen, in the 

 month of October, about, an hour after sunrise, ten 

 or fifteen of them descend from a groat height, and 

 settle on the top of a tall detached tree, appearing, 

 from their silence and sedateness, to be strangers, 

 and fatigued. After a pause of a few minutes, they 

 began to dress and arrange their plumage, and con- 

 tinued so employed for ten or fifteen minutes more; 

 then, on a few warning notes being given, perhaps 

 by the leader of the party, the whole remounted to a 

 vast height, steering in a direct line for the south- 

 west. In passing along the chain of the Bahamas 

 towards the West Indies, no great difficulty can 

 occur, from the frequency of these islands ; nor even 

 to the Bermudas, which are said to be six hundred 

 miles from the nearest continent. This may seem 

 an extraordinary flight for so small a bird ; but it is, 

 nevertheless, a tact that it is performed. If we sup- 

 pose the blue-bird in this case to fly only at the rate 

 of a mile per minute, which is less than I have actu- 

 ally ascertained him to do over land, ten or eleven 

 hours would be sufficient to accomplish the journey; 

 besides the chances he would have of resting by the 

 way, from the number of vessels that generally navi- 

 gate those seas. In like manner, two days.at most, 

 allowing for numerous stages for rest, would conduct 

 him from the remotest regions of Mexiro to any part 

 of the United States." Many blue-robins, however, 

 it would appear, never leave the United Slates' terri- 

 tory, a few solitary individuals being seen there oven 

 in the depths of winter, especially about the cedar 

 trees, whence they issue and approach the cultivated 

 grounds at every interval of fine weather. 



The blue-robins are interesting birds, not only 

 from their pleasing familiarity, but from their general 

 distribution and number of the individuals in North 

 America, where they are the only Saxicalince, and 

 where they consequently appear to occupy the sta- 

 tion, and to perform the office, which in other parts 

 of the world, are filled by a considerable number of 

 birds, of various species, and even genera. They are 

 birds which follow cultivation, and have doubtless 

 greatly increased in numbers since the country was 

 reclaimed by Europeans, and will still continue to 

 increase, as the forests are cut down, and their sites 

 become adapted to their habits. 



BLUE-BOTTLE, or FLESH-FLY. The Musca 

 vomitoria, Liutuuns, and several other allied species of 

 dipterous insects, are ordinarily known under this 

 name. They are amongst the largest species of the 

 genus found in this country, and generally of a blue 

 colour, whence their name ; some species, however, 

 with similar habits, are green, as the Musca Ccesar. In 

 their habits, however, they very nearly resemble the 

 blow-fly, but with this principal difference, namely, 

 that they are deposited in the form of eggs by the 

 parent flies. But here, again, we find nature equally 



Note to Jardine's Edition of Wilson. Vol. i. p. 60, 61. 



rich in resources, since the eggs, instead of lying for 

 days or weeks in an unhatched state, as is generally 

 the case with insect eggs, are hatched in the course 

 of a couple of hours. The insatiable voracity of 

 the grubs hatched from these eggs is not less than 

 that of the blow-fly. Of this Messrs. Kirby and 

 Spence have given a remarkable instance, in which 

 these flies attacked the living body of a poor man 

 who incautiously laid himself down in a field, having 

 been taken rather unwell, the flies being, in the first 

 instance, attracted by pieces of meat which he had 

 begged and placed between his shirt and his skin ; 

 and to such a degree did the grubs swarm upon his 

 body, eating into it in all directions, that he only 

 survived the operation of cleansing his body from 

 them for a tV'w hours. A recent writer has attempted 

 to call in question the unerring instinct of insects in 

 the deposition of their eggs upon those substances 

 most congenial for the food of the young when 

 hatched, and has instanced, in support of his at- 

 tempts, the case of the common blow-fly, Musca 

 vomitoria (or rather M. carnaria), which sometimes 

 lays its eggs in the foetid funguses (phalli, agarici,$tc.), 

 " apparently under the notion that these are genuine 

 carrion." Insect Transformations, p. 76. We appre- 

 hend, however, that the only notion entertained by 

 the insect is, that the substance upon which the eggs 

 are deposited will serve for food for its young, which 

 it does most effectually. Thus this mistaken "notion" 

 tells against the writer's argument. We have seen 

 the carrion plants, Hoija carno&a, swarming with grubs, 

 which there obtain an abundant supply of food, as 

 figured by Rosel (Muscidum ct Culicicm, plate 9, 10.) 

 From the experiments of Spallanzani, it appears that 

 these grubs are able to withstand a heat of 88 

 Fahrenheit, but that they perished when it was raised 

 to 108. These experiments were conducted with so 

 much care, that we cannot hesitate in considering Dr. 

 Good's statement, that eggs of the blow-fly deposited 

 upon meat, and broiled with it upon a gridiron in a 

 heat far beyond 212", instead of being destroyed, are 

 thereby quickened into their larvae state. The ap- 

 pearance of maggots on broiled meat, as judiciously 

 observed in the work above referred to, p. 119, from 

 which the inference is apparently made, seems rather 

 to indicate that eggs, or more probably ovo-viviparous 

 larva?, had been deposited there, not before, but after 

 the broiling. 



BLUE BREAST; SWEDISH, or BLUE 

 BREASTED FANTAIL. (PandiciUa Suecica; 

 Motacilla Succica of Linnueus.) A small European 

 bird, which lately has been added to the list of strag- 

 glers to the British islands, a specimen having been 

 killed in an undoubted wild state, upon a common, 

 near Newcastle upon Tyne. In size and form it much 

 resembles the different redstarts (Plucmcura, Swam- 

 merdam), but differs from them in several minor 

 particulars, and especially in its mode of progression, 

 which is always ambulatory, or by alternate steps, 

 and never by successive hops, as in those birds. The 

 crown of the head and rest of the upper parts are 

 brown, the latter tinged with greyish, and paler on the 

 margins of the scapulars and wing-coverts ; feathers 

 at the base of the bill, and streak over the eye, yel- 

 lowish white. The chin, throat, and upper part of 

 the breast, rich azure, with a silky white spot in the 

 centre ; the blue bordered beneath with a narrow 

 gorget of black, which is succeeded by another of 

 reddish brown. Under parts dirty white, inclining to 



