suck the blood of larger animals; though we do not recollect that what we refer to has been noticed by naturalists. Our attention was directed to the circumstance many years ago in Scotland, where the midge (Culicoides punctata, LATR.), a very small kind of gnat, was so very troublesome to a party of hay-makers, that it was with difficulty they could continue their work; yet, notwithstanding the general attack made by the insects wherever they could find a spot of uncovered skin, one individual among the hay-makers was never touched, while the skin of his companions was covered with bites as if scourged with nettles. It was evident, therefore, that the midges, though otherwise apparently indiscriminate in their attacks, did not relish the blood of this individual, from some unknown peculiarity of constitution or of disease*. The midge is not so troublesome in the neighbourhood of London as the gnat. Derham says, "these gnats are greedy bloodsuckers, and very troublesome where numerous, as they are in some places near the Thames, particularly in the breach waters that have lately fallen near us in the parish of Dagenham, where I found them so vexatious that I was glad to get out of these marshes: yea, I have seen horses so stung with them, that they have had drops of blood all over their bodies where they were wounded by them. Among us in Essex they are called Nidiots t."

A similar selection of individuals even of the same species is very remarkable in the ox-breeze fly (Hypoderma Bovis, LATR.), which always prefers young cattle of two or three years old, and avoids old cattle in depositing its eggs, as if aware that her progeny would find it harder to penetrate an old, tough hide,

* J. R.

+ Physico-Theology, Book iv. c. 11, No. u. Theatr. Insect., xiii, 82.

See also Mouffet,

while they would likewise fare worse after they had effected a lodgment *; but whether this selection is made through the medium of taste, smell, touch, or vision, we have no means of ascertaining.

The midge, however, is by no means peculiar in its apparent capriciousness of taste; for the same preference and antipathy is exhibited by most of the other blood-sucking insects. Of two individuals, for example, who had been together for a whole day on a nutting expedition, and who slept in the same bed-chamber, next morning one was covered all over Iwith red blotches from the attacks of the harvestbug (Leptus autumnalis, LATR.), while the other was quite untouched †. Stewart says that this mite chiefly attacks women and children ‡.

Harvest-bug (Leptus autumnalis), greatly magnified.

A species of this family (Acarina), probably the red tick (Pediculus coccineus, SCOPOLI), or a mite (Leptus Phalangii), described by De Geer, appears to be much more indiscriminate in its tastes; for

* Insect Architecture, page 412.

+ J. R.

Elements, ii. 324.

during the summer of 1830 we found it at Havre de >Grace, infesting insects of the most different families. It particularly abounded on the marbled butterfly (Hipparchia Galathea, LEACH), so that many of them were scarcely able to fly from the exhaustion caused by these little blood-suckers; and so pertinaciously did they retain their hold, that several of them now adhere to the specimens of the butterfly in our cabinet.

Marbled butterfly (Hipparchia Galathea) and caterpillar.

What was most remarkable, although the ringlet butterfly (H. Hyperanthus) was plentiful at the same time, and is similar in food and habits, not one of the parasites was found on some hundreds which we

caught expressly to ascertain the fact. This appears the more strange, that several dragon flies (Libellulina, MAC LEAY) were found as much infested with them as the marbled butterfly. We also more than once found them on field crickets, ants, and beetles, and once on a harvest spider (Phalangium Opilio)*. Another species (Gamasus Coleoptratorum, FABR.) indiscriminately infests the common dung-beetle and the humble-bee (Bombus terrestris), so as often to destroy them; a circumstance which, from its frequent occurrence, may have caught the observation of persons who otherwise pay little attention to insects.

The parasite which thus infests the bee and the dung-beetle, however, is not so pertinacious in adhering to its victim as those which died of hunger rather than quit our butterfly specimens. The bee mite, on the contrary, though not very easily dislodged while the insect is alive, immediately scampers off as soon as it dies, and even long before, when it becomes sickly from the irritation of the numbers by which it is infested, as we have often witnessed by confining insects thus attacked. Whether this arises from their finding it more difficult to penetrate the skin, or from their not relishing the diseased fluids, we cannot tell. That the latter is the more probable reason, appears from another curious fact connected with our immediate subject, namely, that fleas and other parasitic insects never infest a person who is near death; and so frequently has this been observed, that it has become one of the popular signs of approaching dissolution. This is in all probability caused by the alteration in the state of the fluids immediately under the skin, either in quality or quantity. It must be upon the same principle that women and children are always more infested with the bed-bug (Cimex lectularius) and other parasitic insects, than old men, * J. R.

whose subcutaneous fluids are scanty, and their skin, in consequence, more rigid and dry.

That insects correct their sense of smell by means of taste appears from numerous observations. Lehmann, for example, tells us, that being taken ill while he was eagerly studying the senses of insects, and was using a bitter decoction of wormwood, he observed a fly (Musca domestica) pounce upon a bit of sugar which had been accidentally moistened with the medicine. It began to suck the sugar, but upon tasting the bitter it instantly flew off to a contiguous vase, and endeavoured to reject the nauseous drug*. It is in a similar way that flies, when they become troublesome in apartments by their great numbers, are lured to their destruction by poisoned waters sweetened with honey or sugar. Corrosive sublimate (Perchloride of Mercury) and king's yellow (Sesqui Sulphuret of Arsenic) are the poisons most usually employed for this purpose; and we cannot too strongly warn our readers that it is dangerous to leave them in the way of children, or even to have any sort of food near upon which the poisoned flies may alight. Infusion of quassia, however, is equally effectual, and quite safe. The fact of the flies sucking up the poisoned water at all, may be adduced to prove that the flies are destitute of taste, in the same way as it may be said that birds or fishes who poison themselves with food drugged with nux vomica do not taste what they are eating; but the argument will not apply, for the taste of the poison is artfully disguised, and it might as justly be argued that Majendie's maid-servant was destitute of taste when she poisoned herself with prussic acid, deceived by its fine nutty flavour into the notion that it was something very nice t.

*De Sensibus Externis, p.36. See Insect Transformations, p. 77.`