17S 



THE ^:^•OI,XTTION ruEdh'Y 



catorpillarw ot" hawk-moths or Sphin^itlai— longitudinal striping, 



ohliqni'ly tran.s\orso striping, and spots. Longitudinal stri}>ing puro 



and nnn\ixod is now found only in a low spot'ios, for instance 



in the caterpillar of the Miicnnilofitit! ><t<i/((tartnn (Fig. 115), in 



which a white longitudinal line, beginning at the tip ol' the tail, 



riuis up each side of the body to the head as a 'subdorsal stripe' 



(^Ih/). These, with other two similar stripes, I'tlectively seem-e 



the fairly large caterjiillar 



from discovery when it is 



among grass and horhs. 



Transverse striping occurs 



as the solo mode of marking 



--, ^ 1 ■,, i,i, ,T ■ ,■ , in species which live on bushes 



I'm. 115. OntovpiUnr 01 tlio 1-Iummini; bud ^ 



Hiiwk-moih, .Udriiijifo.wn.sWWiinim. .■^^.^ thosuii- and trees who.se leaves have 



dorsal line. . 1 , "T~ • 1 , 



strong lateral venis, such as 



willo ws, p oplars , oaks, privet, syringa, ancl so on, and thest> markings 



associated with tho leaf-green of their colouring jtrotect. them most 



ett'ectively from discovery. 



The third scheme of marking, namely by spots, ticcurs in varimis 



forms in species of the genera Deilc/i/iiht and Chwrovdiii/Hi. and it 



varies in its biological signiticance ; in many species the spots ser\e 



as a warning colour, by making the caterpillar conapicuoua and easily' 



seen from a distance {DeilcphUa galiU Fig. \\')\ in others they 



imitate the eyes of a larger animal, and ha\e a 'terrifying' elfect, 



as we ha\(> alrea(l\- said (Fit:. 4); in still otlu-r and rarer cases they 



heighten the resemblance 



of tho caterpillar to its 



I'ood-plant by mimicking 



parts of it, as, for instance, 



the red berries of tho 



buckthorn {Dcili-phiht, 



hip/>o/)/itirn, I'^'ig. S, ■(•). 



Thus all three modoa 



of marking jmssess a biological \a,hie, and ]n-otect tho soft and 



easily wounded animal in somo way, and, in the casi' of at least 



two of them, it is clear that tlu>y must ha\e arisen at tho very 



end of the caterpillar's de\'elopment, since* th(\y can only be ellec- 



tivo as tho animal is approaching full size, and would bo \alnelesH 



in tho very young caterpillar. Tin* transverse striping only makes 



the caicrpillar like a len,f when the strijies bear about the same 



reflation to each other as thoso on tho l(>af, and ((ye-spots can only 



scare away lizards and birds when they a.re of a certain size. Only 



Fig. 3 (ropoiUod). Full-i;i"vvii onti'i-pillm- of llu> 

 Eyed llawk-motli, SiiHirinllni.-^ oirllaliis. si), Iho nuIi- 

 ddi'siil ati'ipo. 



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