MEANS OF DEFENCE OF INSECTS. 411 



of a gentle hill. In the midst of these boiling springs, within three feet 

 of five or six of them, rises a tepid one about blooil-vvarm. But the 

 most extraordinary circumstance which he relates is, that not only con- 

 fervas were found in the boiling springs, but numbers of small black beetles, 

 that died upon being taken out and plunged into cold water.^ — And 

 once, having taken in the hot dung of my cucumber-bed a small beetle 

 (St/ncfiita Jughmdis), I immersed it in boiling water ; and, after keeping it 

 submerged a sufficient time, as I tliought, to destroy it, upon taking it out, 

 and laying it to dry, it soon began to move and walk. Its native station 

 being of so high a temperature, Providence has fitted it for it, by giving it 

 extraordinary powers of sustaining heat. Other insects are as remarkable 

 for bearing any degree of cold. Some gnats that De Geer observed, 

 survived after the water in which they were was frozen into a mass of ice: 

 and Reaumur relates many similar instances.^ 



The last passive means of defence that I mentioned, was the multiplica- 

 tio7i of insects. Some species, the Aphides for instance, and the Grass- 

 hoppers and Locusts, have such an infinite host of enemies, that were it 

 not for their numbers the race would soon be annihilated. — But as passive 

 means of defence have detained us sufficiently long, it is enough to have 

 touched upon this head. Let us then now proceed to such as may be 

 called active; in which the volition of the animal bears some part. 



II. The active means of defence, which tend to secure insects from 

 injury or attack, are much more numerous and diversified than the pas- 

 sive ; and also more interesting, since they depend, more or less, upon the 

 efforts and industry of these creatures themselves. When urged by danger, 

 they endeavour to repel it, either by having recourse to certain attitudes 

 or motions ; producing particular noises ; emitting disagreeable scents or 

 fluids ; employing their limbs, or weapons, and valour ; concealing them- 

 selves in various ways, or by counteracting the designs and attacks of 

 their enemies by contrivances that require ingenuity and skill. 



The attitudes which insects assume for this purpose are various. Some 

 are purely imitative, as in many instances detailed above. I possess a 

 diminutive rove-beetle {Aleochara compUcans K. Ms,), to which my atten- 

 tion was attracted as a very minute, shining, round black pebble. This 

 successful imitation was produced by folding its head under its breast, and 

 turning up its abdomen over its elytra; so that the most piercing and dis- 

 criminating eye would never have discovered it to be an insect. I have 

 observed that a carrion beetle (^Sitpha thoracica} when alarmed has re- 

 course to a similar manoeuvre. Its orange-coloured thorax, the rest of 

 the body being black, renders it particularly conspicuous. To obviate this 

 inconvenience, it turns its head and tail inwards till they are parallel with 

 the trunk and abdoKien, and gives its thorax a vertical direction, when it 

 resembles a rough stone. The species of another genus of beetles (/iga- 

 thidium) will also bend both iiead and thorax under the elytra, and so 

 assume the appearance of shining globular pebbles. 



Related to the defensive attitude of the two last-mentioned insects, and 

 precisely the same with that of the Armadillo (Dasi/pus) amongst qua- 

 drupeds, is that of one of the species of woodlouse (Armadillo vulgaris). 



l J. Mason Good's Anniversary Oration, delivered March 8. 1808, before the Me- 

 dical Society of London, p. 31. 

 * De Geer, vi. 35o. ; comp, 320., and Reaum. 11. 141 — 147. 



