si* OF INSTINCT. ccT,XVI.i5. 



ing the means by which they acquire this know- 

 ledge. 



The care of the falmon in choofing a proper 

 Situation for her fpawn, the ftruclure of the nefts 

 *>f birds, their patient incubation, and the art of 

 the cuckoo in depofiting her egg in her neighbour's 

 jmrfery, are inftances of great fagacity in thole 

 creatures : and yet they are much inferior to the 

 arts exerted by many of the infe6t 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 produced than, chofen by the mother in- 

 fed for the convenience of her offspring. The 

 cells of bees, waips, fpiders, and of the various 

 coralline infects, equally aftonim us, whether we 

 attend to the materials or to the architecture. 



But the conduct of the ant, and of iorne fpecies 

 of the ichneumon fly in the incubation of their 

 eggs, is equal to any exertion of human fcicnce. 

 The ants' many times in a day move their eggs 

 Dearer the furface of their habitation, or deeper be* 

 low it, as the heat of the weather varies ; and ia 

 colder days lie upon them in heaps for the purpofe 

 of incubation ; if their manfion is too dry, they 

 carry them to places where there is moifture, and 

 you may diftinclly fee the little worms move and 

 ick up the water. When too much moifture ap- 

 proaches their neft, they convey their eggs deeper 

 in the earth, or to fome other place of fafety, 

 (Swammerd. Epil. ad Hift. Infects, p. 153. Phil, 

 Jranf. No. 23. Lowthorp, V. 2. p. 7.) 



There is one fpecies of ichneumon-fly, that digs 

 a hole in the earth, and carrying into it two or three 

 living caterpillars, depofits her eggs, and nicely 

 clofing up the neft leaves them there ; partly doubt- 

 lefs to ajlift the incubation, and partly to fupply 



food 



