OF INSTINCT. SECT. XVI 15. i. 



door, whenever they pafs or repafs. This hiftory was told me, 

 and the neft with iis operculum (hewn me by the late Dr. Butt 

 of Bath, who was fome years phyiician in Jamaica. 



The produftion of thefe nets is indeed a part of the nature 

 or conformation of the animal, and their natural ufe is to fup 

 ply the place of wings, when Ihe wimes to remove to another 

 fituation. But when {he employs them to entangle her prey, 

 there are marks of evident defign, for fhe adapts the form of 

 each net to its fituation, and ftrengthens thofe lines, that require 

 it : , by joining others to the middle of them, and attaching thofe 

 others to diftant objeb, with the fame individual art, that is 

 ufed by mankind in fupporting the mafts and extending the 

 fails of (hips. This work is executed with more mathematical 

 exaftnefs and ingenuity by the field fpiders, than by thofe in 

 our houfes, as their conftruUons are more fubjeled to the in- 

 juries of dews and tempeits. 



Befides the ingenuity (hewn by thefe little creatures in taking' 

 their prey, the circumftance of their counterfeiting death, when 

 they are put into terror, is truly wonderful j and as foon as the 

 objeft of terror is removed, they recover and run away. Some 

 beetles are alfo faid to poflefs this piece of hypocrify. 



The curious webs, or cords, conftruled by fome young cat- 

 erpillars to defend themfelves from cold, or from infers of prey 

 and by filk-worms and fome other caterpillars, when they tranf- 

 migrate into aurelixor larvae, have defervedly excited the admi- 

 ration of the inquifitive. But our ignorance of their manner of 

 life, and even of the number of their fenfes, totally precludes 

 us from underftanding the means by which they acquire this 

 knowledge. 



The care of the falmon in choofmg a proper fituation for her 

 fpawn, the ftrudure of the nefts of birds, their patient incuba- 

 tion, and the art of the cuckoo in depofiting her egg in her neigh- 

 bour's nurfery, are inftances of great fagacity in thofe creatures : 

 and yet they are much inferior to the arts exerted by many of 

 the infeft tribes on fimilar occafions. The hairy excrefcences 

 on briars, the oak apples, the blafted leaves of trees, and the 

 lumps on the backs of cows are fituations that are rather produ- 

 ced than chofenby the mother infed for the convenience of her 

 offspring. The cells of bees, wafps, fpiders, and of the various 

 coralline infects, equally aftonifh us whether we attend to the 

 materials or to the architedure. 



But the condudl of the ant, and of fome fpecies of the icji- 

 neumon fly in the incubation of their eggs, is equal to any exer- 

 tion of human fcience The ants many times in a day move 

 their eggs nearer the furface of their habitation, or deeper be* 



Jow 



