ArrENDix. 373 



hold in corporeal structures, namely, that the parts which 

 diller most in allied species, are apt also to vary most in the 

 same species. Another Bee, the Megachile maritima, as I am 

 informed by Mr. Smith, near the sea makes its burrows in the 

 sand-banks, whilst in wooded districts it bores holes in posts* 



I have now discussed several of the most extraordinary 

 classes of instincts ; but I have still a few miscellaneous 

 remarks which seem to me worth making. First for a few 

 cases of variation which have struck me : a spider which had 

 been crippled and could not spin its web, changed its habits 

 from compulsion into hunting — which is the regular habit of 

 one large group of spiders. t Some insects have two very 

 different instincts under different circumstances, or at different 

 times of life ; and one of the two might through natural selec- 

 tion be retained, and so cause an apparently abrupt difference 

 in instinct in relation to the insects' nearest allies: thus the 

 larva of a beetle (the Cionus scrophuluria), when bred on the 

 scrophularia, exudes a viscid substance, which makes a trans- 

 parent bladder, within which it undergoes its metamorphosis ; 

 but the larva when naturally bred, or transported by man, on 

 to a verbascnm, becomes a burrower, and undergoes its meta- 

 morphosis within a ieaf.J In the caterpillars of certain moths 

 there are two great classes, those which burrow in the paren- 

 chyma of leaves, and those which roll up leaves with consum- 

 mate skill : sonte few caterpillars in their early age are 

 burrowers, and then become leaf-rollers; and this change was 

 justly considered bo great, that it was only lately discovered 

 that the caterpillars belonged to the .same speciesj The 

 Angoumois moth usually has two broods: the first are 

 hatched in the spring from eggs laid in the autumn on grains 

 of >>>vn stored in granaries, and then immediately take flight 



to the Gelds and lay their eggs on the standing corn, instead 

 of "ii the naked grains stored all round them: the moths of 

 sond brood (produced from the eggs laid on the standing 

 i ra are hatched in the granaries, and then do not leave the 

 granaries, but deposit their eggs <>n the grains around them ; 

 ami from i '• proceed toe vernal brood which have the 



• [ Here follows n *<•< i ion on the iostinctaof P i, Slare making, ami 



Ccll-in:i!iiiii. , 1 » lurli it published in the Origin "f Spt cie* - 1 1 . -I . li.J 

 f Quotod on authority of Sir J. Bank* in Journ al Ltaa, 800, 



I P HiiImt in Mini. 80c. I'lt-i*. d G •■ . tome *, ]>. ii.'J. 

 § Wi-slttuud, 111 (JarJcnoi L'hmiurle, I'i'/J, \i 861, 



