COLOURS AND FORMS OF INSECTS. 147 



persuaded, liowever, that neither a bird, an ichneu- 

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

 such a mistake. 



This family of caterpillars {Gcomclridte, 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 iiave 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 prolegs, 

 they stretch out tlieir heads to the full extent of their 

 body, laying hold with tiieir fore legs while they bring 

 forward their body into the n tbrm again. 



Sncli are among the most prominent examples ad- 

 duced by naturalists who advocate the theory that 

 these resemblances to inanimate ol)jects are intended 

 to conceal insects from their enemies.* We shal/ 

 now give a iew instances which have suggested 

 themselves as no less corroborative of the op|)osit0 

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

 surveyor caterpillars, whose movements we iiave just 

 been describing, found very commonly on the cur- 

 rant, tlie gooseberry, and the black thorn, and called 

 by collectors the magpie {Abraxas Grossulariata , 

 Leach.) This caterpillar is very conspicuous from 

 being spotted, somewhat like the |)erfect 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 (Cucu'lia ScmpJiiiIarioi, Hubner), 

 and of the burnet moth {EncUd'm GUjphica, Och- 

 SENUEi.^i.), 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 Kirby and Spence, Intr. ii, 219-237. 



