MUSCULAR STRENGTH OF INSECTS. 185 



chinery, it has survived in a miraculous manner. 

 Such is the account originally given by Linnaeus.* 

 A recent compiler, mistaking Kirby and Spence's 

 very apt comparison of this grub to a London porter 

 nicknamed Leather-coat-Jack, from his being able to 

 suffer carriages to drive over him without receiving 

 any injury, forthwith fancies the porter to be ' another 

 insect, called leather- coat-jack,' which ( will bear 

 heavy carriage wheels to pass over it with impunity.' 

 Since the grub in question is rather soft, it must be 

 the tough texture of the skin which preserves it, as 

 in the similar instance of the caterpillar (figured at 

 page 125) of the privet hawk-moth (Sphinx Ligustri), 

 which Bonnet squeezed under water till it was as flat 

 and empty as the finger of a glove, yet within an hour 

 it became plump and lively as if nothing had happen- 

 ed.! 



The instances, however, which we have just re- 

 corded are peculiar rather than general, for caterpillars 

 are for the most part very easily bruised and other- 

 wise injured. Those which are large and heavy, 

 therefore, such as the caterpillars of the hawk-moths 

 (Sphingidai), have the power of attaching themselves 

 very firmly to the spots where they feed and rest by 

 means of the numerous hooks of their pro-legs,J so 

 that it is almost impossible to detach them from the 

 branch to which they are clinging; and hence col- 

 lectors always cut the branch itself. All of them 

 have the means of breaking their fall by spinning a 

 cable of silk, which they uniformly do when acciden- 

 tally forced to quit their situation. Their method of 

 climbing up this cable again is worthy of observation, 

 for it differs considerably from the manoeuvre of spi- 

 ders, under the same circumstances; as must be ob- 



* Fauna Suecica, 1799. 



t lionnet, (Euvres, vol. ii, p. 124. 



$ See Insect Architecture, p. 307, right-hand figure. 



VOL. VI. 16* 



