OF NATURAL HISTORY. 157 



attention. Though fhe feeds not upon flefli herfelf, and 

 certainly knows not that an animal is to proceed from the egg, 

 and far lefs that this animal muft be nourifhed wiih other 

 animals, fhe collets ten or twelve fmall green worms, which 

 (he piles one above another, rolls them up in a circular form, 

 and fixes them in the hole in fiich a manner that they cannot 

 move. When the wafp-worm is hatched, it is amply ftored 

 with the food Nature has deflined for its fupport. The green 

 worms are devoured in fucceflion ;* and the number depofited 

 is exaftly proportioned to the time necelTary for the growth 

 and transformation of the wafp-worm into a fly, when it 

 iffues from the hole, and is capable of procuring its own 

 nourifliment.f 



There are many other inftances of ichneumon wafps and 

 flies, which, though they feed not then^felves upon worms, 

 lay up provifions of thefe animals for the nourilhment of 

 their young ; and each kind is adapted to the conflitution or 

 the worm that is to proceed from their eggs. J 



Birds of the fame fpecies, unlefs when reftrained by pecu- 

 liar circumftances, uniformly build their nePi.s of the fame 

 materials, and in the fame form and fituation, though they 

 inhabit very different climates. When removed by necfefiity 

 from their eggs, they haften back to them with anxiety. 

 They turn and faift their eggs, which has the eff-'£l of heat- 

 ing them equally. Ducks and gez^s cover up their eggs till 

 they return to the ned. A hen fits w^ith equal ardour upon 

 eggs of a different fpecies, or even upon artificial eggs. I 

 have often contemplated with wonder an inftindl of the fwal- 

 low. When her offspring are very young, like other fmall 

 birds, file carries their excrements out of the ned. But, after 

 they are older, fhe attaches herfeif to tm fide of the reft, 

 and by fome geilurel and founds, folicits the young to void 



* Reaumur, torn, la, n.-^ge iS, t IbM, psgc aa. — ii- 

 ^Ileaumur, coin. ii. page 5S. 



u 



