SELF-PRESERVATION. f)07 



beetles, carrion-beetles, carrion-flies, wasps, &c., emit, upon being 

 touched, such a nauseous stench, that this must prevent every insectivo- 

 rous bird from using them as food. 



Another peculiarity which may be also classed among the passive 

 means of defence is their tenacity of life, and for which they have to 

 thank, in the first place, an organisation adapted to all possible circum- 

 stances, and, secondly, their hard exterior integument. The latter 

 acquires in many insects, particularly the beetles, such hardness, that 

 it is with difficulty that their elytra can be pierced. This is especially 

 the case with the large Curculios, for instance, the species of the genus 

 Cleonis, Lixus, Otiorhynchus, &c., then in the Hislers, which have 

 so firm an integument, that, upon any but a stony surface, they may 

 be trod on with impunity, and are more easily pressed into the ground 

 than crushed. This is partly the case also with the Byrrhi This 

 hard clothing is not found exclusively among the beetles ; in the 

 otherwise soft Diptera there is an instance of the kind, namely, in the 

 louse-fly of the sheep (Melophagus ovinus), which cannot be crushed 

 between the fingers ; and the smaller parasites, as the louse and the 

 flea, are difficult to crush in this manner. Respecting the tenacity of 

 life with which they, even wounded or mutilated, resist death, we have 

 before cited instances. Impaled insects will live thus for several weeks, 

 and at last appear to die less from the effect of the injury than from 

 hunger. I myself have kept Blaps mortisaga for three months without 

 food ; and Rudolphi mentions, in his " Physiology," an instance which 

 Schuppel communicated to him, of an. insect of the same family which 

 this skilful entomologist received from the South of France, which, 

 although impaled, arrived alive in Berlin, and here even continued still 

 to live for some time. Other cases, in which beetles have been enclosed 

 in wood for years without any food, have been communicated by other 

 writers ; and instances of insects remaining torpid in spirits of wine 

 for several hours, and indeed days, and yet be re-aroused from their 

 sleep upon being brought into the air, I have previously mentioned. 

 They still longer retain their life in water. According to Lyonet, the 

 caterpillar of Cosms iigniperda will live nearly three weeks beneath 

 water ; and according to Curtis, the plant lice will survive for sixteen 

 hours in that element, but die if continued for twenty-four. Kirby 

 and Spence relate, after Reeve, instances in which in warm foun- 

 tains, the temperature of which was about 205 Fahr., he has found the 

 larvae of Tipulte ; and Good has observed little black beetles, probably 



