MUSCULAR STRENGTH OF INSECTS. 185 



cliinery, it has survived in a miraculous manner. 

 Such is the account originally ^iven by Linnaius*. 

 A recent compiler, mistaking Kirby and Spence'svery 

 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 ol 

 the caterpillar (figured at page 125) of the privet 

 hawk-moth {Sphinx Ligudri), 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 happened f. 



The instances, however, which we have just re- 

 corded are peculiar rather than gtneral, for cater- 

 pillars are for the most part very easily bruised and 

 otherwise injured. Those which are large and heavy, 

 therefore, such as the caterpillars of the hawk-moths 

 (^Sjj/iingidfe), have the powerof 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 alwajs 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 acci- 

 dentally forced to quit their situation. Their method 

 of climbing up this cable again is worthy of observa- 

 tion ; for it differs considerably from the manoeuvre 

 of spiders, under the same circumstarices, as must Ixj 



* F'auna Suec.ica, 1799. 



t Bonnet, Giluvr-es, vol-, ii.p. 124. 



4 See Ini^ecl Architecture, p. 307, right-hand figure. 



