11' EXTERNAL ANATOMY OF INSECTS. 



fluids ; its mouth requires no hardness ; the bulk of its head 

 and body offers an obstruction to its obtaining a sufficient 

 supply of its food, which is generally concealed in the nectary 

 of flowers ; the passage to the ocsojj/tagu.i is lengthened, and 

 the difficulty overcome. The caterpillar produces the butter- 

 fly; one is haustellate, the other mandibulate : they cannot be 

 placed in separate classes. The mouth sometimes varies as 

 much and as abruptly in the same insect in its different stages, 

 as in any two different insects in their final stage. In others 

 it remains nearly the same, or gradually approaches its 

 perfection with every change of skin. In Oithoplcra and 

 Ilemiptera the latter is the case : in these classes, every 

 ecdysis is a metamorphosis ; the food and economy undergo 

 no change, the organs therefore require none. Nature never 

 provides uselessly. Fabricius beautifully observes, that it is 

 the part of the wise man to study these things ; to observe, 

 record, and add them to the stores of science ; to weigh well 

 the mysteries of Nature, and trace the hand of a Creator in 

 the wonders of his creatures. Lamarck says, that each 

 peculiar form has been acquired by degrees," and by striving to 

 attain a particular object." He appears to have forgotten, that 

 if honey had been denied to the bee until its little mouth had 

 lengthened out into a thread-like tube, starvation and extinc- 

 tion of its race must have been the consequence. Kirby, in 

 reference to this, exclaims, It is grievous that this eminent 

 zoologist, who in other respects stands at the head of his 



° La nature, dans toufes ses opi5rations, ne pouvant proc6der que graduelle- 

 ment, n'a pu pioduire tous les animaux i\la-fois : elle n'a d'abord forme que les 

 plus simples ; et passant dc ceux-ci jnsqu'au plus compost's, elle a ctabli suc- 

 cessivement en eux difierens systemes d'oi'ganes particulicrs, les a multiplies, en 

 a augment^ de plus en plus I'^nergie, et, les cumulant dans les plus parfaits, elle 

 a fait exister tous les animaux connus avec I'organisation et les facultfe que nous 

 leur observons. — Lnmanlt. An. sans Vert. 



" Prcmifiremcnt, quantity de fails connus prouvent que I'emploi soutcnu d'un 

 organc concourt ;\ son devcloppement, le fortifie, et I'agrandit meme j tandis 

 qu'un defaut d'emploi, dcvenu liabituel a I'^gard d'un organe, nuit k ses develop- 

 peraens, le deteriore, le r^duit graduellement, et finit par le faire disparoitrc, si 

 ce defaut d'emploi subsiste, pendant une longue duree, dans tous les individus 

 qui se succ^dent par la generation. On con9oit de 1.1 qu'un changement de 

 circonstances foryant les individus d'unc race d'animauxa changer leur habitudes, 

 les organcs moins employes d('perissent peu il pen, landis que ceux qui le sont 

 davaiitage, se d6veloppent mieux et accpiiiircnt une vigucur et des dimensions 

 proportionnelles 4 I'emploi que ces individus en font habiluellenieiit. — Laniard;. 

 Phil. Zool. 



