COLOURS AND FORMS OF INSECTS. 147 



persuaded, however, that neither a bird, an ichneumon, 

 nor a naturalist, would have been apt to fall into such 

 a mistake. 



This family of caterpillars {Geomdridee, Stephens) 

 have been by collectors not inappropriately named 

 surveyors, loopers, and geometers, from their peculiar 

 manner of moving-, which may readily be conceived 

 by those who have not seen them, when we mention 

 that at the commencement of each step their bodies 

 present a pretty exact figure of the Greek letter 12. 

 In this position, laying hold with their hinder pro-legs, 

 they stretch out their heads to the full extent of their 

 body, layi-ng hold with their fore legs while they bring 

 forward their body into the Q> form again. 



Such are among the most prominent examples ad- 

 duced by naturalists who advocate the theory that 

 these resemblances to inanimate objects are intended 

 to conceal insects from their enemies *. We shall 

 now give, a few instances which have suggested 

 themselves as no less corroborative of the opposite 

 doctrine. The first which occurs to us is one of the 

 surveyor-caterpillars, whose movements we have just 

 been describing, found very commonly on the cur- 

 ! rant, the gooseberry, and the blackthorn, and called 

 by collectors the magpie {Abraxas grossulariata. 

 Leach). This caterpillar is very conspicuous from 

 being spotted, somewhat like the perfect insect, with 

 black upon a bright yellow ground, and contrasting 

 strongly both with the deep green of the leaves upon 

 which it feeds, and the dark-coloured bark upon 

 which it usually rests. The caterpillars of the water- 

 betony moth {CucuUia Scrophularice, Hubner), 

 and of the burnet-moth {Euclidia Glyphica, Ocii- 

 senheim,), are similarly marked with deep black on a 

 yellow ground, which must render them very conspi- 

 cuous. The caterpillars of the small tortoise-shell 



* See Kirhy and Spenre, Ttitr. ii. 21')-237. 



K :? 



