442 H VBLilNATION Olf INSECTS* 



depart from this rule. Thus Aphis Rosce^ Cardui^ and 

 probably many others of the genus, hybernate both in 

 the egg and perfect state ^ ; Papilio Cardui, Rhamni, 

 and some other species, usually in the pupa, but often 

 in the perfect state also ; and Papilio lo, according to 

 the accurate Brahm, in the three states of egg, pupa, 

 and imago''. It is probable that in these instances the 

 perfect insects are females, which, not having been 

 impregnated, have their term of life prolonged beyond 

 the ordinary period. 



The first cold weather, after insects have entered 

 Iticir winter quarters, produces effects upon them si- 

 milar to those which occur in the dormouse, hedgehog, 

 and others of the larger animals subject to torpor. 

 At first a partial benumbment takes place ; but the in- 

 sect if touched is still capable of moving its organs. 

 But as the cold increases all the animal functions cease. 

 The insect breathes no longer, and has no need of a 

 supply of air*^; its nutritive secretions cease, and no 

 more food is required ; the muscles lose their irritabi- 

 lity*^; and it has all the external symptoms of death. 

 In this state it continues during the existence of great 

 cold, but the degree of its torpidity varies witli the 

 temperature of the atmosphere. The recurrence of a 

 mild day, such as we sometimes have in winter, infuses 

 a partial animation into the stiffened animal : if dis- 

 turbed, its limbs and antennas resume their power of 

 extension, and even the faculty of spirting out their de- 

 fensive fluid is re-acquired by many beetles'^. But 



* Kyher in Germar Magazin der Entomologie, ii. 2. 



^ Ins. Kttl. ii. 1S&, '^ Spallanzani, Rapports de I* Air, 8^c. i. 30. 



" Carlisle in Fhil. Trans. 1805, p. 25. * Sclmiid in lUig. Mag. i. 222. 



