240 



THE PHILOSOPHY 



nus. In fome butterflies, for example, the female Is cleftltute of 

 wings, while thofe of the male are very large. The male and fe- 

 male of thofe animals cdiWed gall- in/eds bear no proportion to each 

 other, either in fize or in figure. They adhere for feveral months to 

 the ftems and branches of plants, fhrubs, and trees, without any ap- 

 parent movement. They have every appearance of galls, being of 

 a fpherical or oval figure, from which circumftance they have re- 

 ceived their denomination, and were long confidered as vegetable 

 iubftances deftitute of every degree of animation. Reaumur, how- 

 ever, by a ftridl examination of the changes they undergo, and of 

 their internal llrufture, difcovered that they belong to the animal 

 kingdom. He found that they contained thoufands of fmall eggs, 

 and that, from thefe eggs, fmall animals were produced, which ran 

 about with fome qulcknefs, and fpread themfelves all over the tree 

 or bufli. After fome days, they attach themfelves to the ftem and 

 branches, remain immoveable, and gradually increafe to their full 

 dimenfions, when their bodies are found to contain numbers of eggs. 

 As the perfe£t animal had no apparent motion, and yet multiplied 

 its fpecies, it was firft thought to be an hermaphrodite of a fingular 

 kind, and that it was capable of producing without any foreign aid. 

 But Reaumur difcovered that they were impregnated by fmall flies, 

 and that thefe fmall flies were male gall infecfts. The head, the 

 body, the bread, and the fix limbs of this fly, are of a deep red co- 

 lour ; and the wings, which are proportionally large, are white, 

 bordered with a band of fine carmine red. In the month of April, 

 he perceived numbers of thefe flies wandering about on the gall- 

 Infedts. He obferved that they pierced the covering of the gall- 

 infefts with a kind of fl:ing fliaped like a needle. This circumfl;ance 

 created a fufpicion that thefe flies were the males, and that this was 

 their mode of impregnating the eggs of the female. To afcerlain 

 this point, he opened a number of gall- infects, which had no un- 

 common appearance, and, in fome of thsm, he found the males, in 



every 



