MIMIC BY. 301 



If we were referring to insects in general, and not to these 

 Phasmida in particular, we should not lay such stress on the 

 probability of their enemies in the past being largely reptiles * 

 and birds. No one who has collected insects beneath an electric 

 light, as I have frequently done at Pretoria, attended in the 

 same pursuit with the shadowy rushes of Bats above, and a host 

 of patient Batrachians beneath, can doubt what wholesale insect 

 destroyers are found in the ranks of the Chiroptera and Amphibia. 

 But although I have found all orders of insects attracted by 

 these lights, including Orthoptera — comprising Mantidce, Achetidce, 

 Forficulidce, Blattidce, Gryllidce, and Locustidce — I personally 

 never met with any representatives of the Phasmidce, though of 

 course these insects may also prove to be nocturnal in their 

 habits, and to be also attacked by Bats. But as these animals 

 have not been traced further back than Eocene times, we can 

 scarcely regard them as having proved enemies to the Carboni- 

 ferous Stick-insects. With the Amphibia the case is different, 

 and, according to the late Prof. Martin Duncan, " the most 

 ancient Amphibia appear to have first lived during the Carboni- 

 ferous age, and all were tailed, had pleurodent teeth, simple in 

 their construction. . . . Some were Lizard-like and others were 

 serpentiform. . . . They are the Microsauria (Dawson), and 

 the genera Hylerpeton (Owen), Hylonomus (Dawson), Br achy dices 

 (Cope), and Ophiderpeton (Huxley) are typical." t Here we have 

 a host of contemporary Carboniferous enemies who may indeed 

 have proved a great trial to the existence of unprotected Phas- 

 midce, and who may synchronously with the evolution of them- 

 selves have indirectly caused or induced a protective evolution 

 in the structural form of these insects, by the mutual inter- 

 dependence in those relations of cause and effect which can be 

 expressed by the well-known appellation " natural selection." 

 And so, for the sake of the argument, dismissing even the agency 

 of either reptiles or birds, we still have abundant reason for 

 believing that, though the protective resemblance of these Phas- 

 midce was already acquired in Carboniferous times, the presence 



* " In the earlier periods of the earth's history, reptiles were no doubt 

 the principal enemies with which butterflies had to deal " (Beddard, ' Animal 

 Coloration,' 2nd edit., p. 211). 



f ' Cassell's Nat. History,' vol. iv. pp. 379-80. 



