192 



MEANS OF DEFENCE OF INSECTS. 



over a slow fire 1 , but you will not gain your end; not a joint 

 will they move, nor show by the least symptom that they 

 suffer pain. Do not think, however, that I ever tried these 

 experiments upon them myself, or that I recommend you to 

 do the same. I am content to believe the facts that I have 

 here stated upon the concurrent testimony of respectable wit- 

 nesses, without feeling any temptation to put the constancy 

 of the poor insect again to the test. — A similar apathy is 

 shown by some species of saw-flies (Serrifera), which when 

 alarmed conceal their antennas under their body, place their 

 legs close to it, and remain without motion even when trans- 

 fixed by a pin. — Spiders also simulate death by folding up 

 their legs, falling from their station, and remaining motion- 

 less; and when in this situation they may be pierced and 

 torn to pieces without their exhibiting the slightest symptom 

 of pain. 2 



There is a certain tribe of caterpillars called surveyors 

 ( Geometrce), that will sometimes support themselves for whole 

 hours, by means of their posterior legs, solely upon their anal 

 extremity, forming an angle of various degrees with the 

 branch on which they are standing, and looking like one of 

 its twigs. Many concurring circumstances promote . this 

 deception. The body is kept stiff and immoveable with the 

 separations of the segments scarcely visible ; it terminates in 

 a knob, the legs being applied close, so as to resemble the 

 bud at the end of a twig ; besides which, it often exhibits 

 intermediate tubercles which increase the resemblance. Its 

 colour too is usually obscure, and similar to that of the bark 

 of a tree. So that, doubtless, the sparrows and other birds 

 are frequently deceived by this manoeuvre, and thus baulked 

 of their prey. Rosel's gardener, mistaking one of these cater- 

 pillars for a dead twig, started back in great alarm when upon 

 attempting to break it off he found it was a living animal. 3 



But insects do not always confine themselves to attitudes 

 by which they meditate escape or concealment ; they sometimes, 

 to show their courage, put themselves in a posture of defence, 



1 De Geer, iv. 229. 



2 Smellie, Phil, of Nat. Hist. i. 150. 



3 Rbs. I. v. 27. 



