OF NATURAL HISTORY. 29.^ 



tljelr month, or any of their members ; for they are all im^ 

 prifoned by coverings more or iefs ftrong. No cares occu- 

 py their attention. Deprived of the faculty of motion, they 

 remain fixed in thofe iltuations which they have chofen for 

 their temporary abode, or where chance has placed them, 

 till their final metamorphoiis into flies. Some of them, how- 

 ever, are capable of changing place ; but their movements 

 are flow and painful. Their blood circulates, but in a con^ 

 trary direction from what takes place in the caterpillar ftate ;- 

 for it proceeds from the head toward the tail. Refpiration 

 continues to go on, but the organs are differently fltuatedt 

 In the caterpillar, the principal organs of refpiration were 

 placed at the pofterior part of the body -, but now thefc 

 fame organs are to be found at the anterior part of the ani- 

 mal. In the third period, the infe(^ has acquired that per- 

 fe(St organization which correfponds to the rank it is to hold 

 in the icale of animation. The bonds of the nymph, or of 

 the chryfalis, are now burft afunder, and the infe6t commenc- 

 es a new mode of exiftence. All its members, formerly foft, 

 inactive, and folded up in an envelope, are expanded, 

 ftrengthened, and expofed to obfervation. Under the form 

 of a worm or caterpillar, it crawled •, under thofe of a 

 nymph, or chryfalis, its power of motion was almofl: annihi- 

 lated j under the lafl: form, it is furnifhed with fix fpringy 

 legs, and two or four wings with which it is enabled to fly 

 through the air. Infliead of teeth or pincers, with which it 

 divided a grofs aliment, it has now a trunk by which it ex- 

 tracts the refined juices of the mofl: delicate flowers. Inflead 

 of a few fmooth eyes which it poflTefl^ed in the worm or cat- 

 erpillar fbate, the new infe£l is furniflied with both fmooth 

 and convex eyes, to the number of feveral thoufands. 



The internal parts of the infect have likewife undergone 

 as many changes as the external. The texture, the propor- 

 tions, and the uumber of the- vifccra, are greatly altercdv 



