LEEUWENHOEK 207 



found, and Leeuwenhoek concluded that the viviparous 

 females were unfertilised. Winged aphids appeared 

 among the rest, and the gradual protrusion of wings 

 beneath the skin was studied ; both winged and wingless 

 forms were viviparous. Leeuwenhoek evidently believed 

 that all, when mature, acquired wings, as his experience 

 of other insects would naturally suggest, but his supposi- 

 tion is not confirmed by observation. 



He notes all sorts of facts concerning aphids in the 

 simple order of discovery, the casting of the skin, the 

 excretion of honey-dew, hitherto believed to fall from 

 the sky, the different species and the restriction of each 

 to a particular plant, the Hymenoptera parasitic upon 

 them, &c. A great deal of new and surprising informa- 

 tion was suddenly thrown out for the consideration 

 of naturalists in these unmethodical and almost extem- 

 pore letters. One figure of an aphis shows the antennae, 

 the proboscis and the abdominal tubes, with a drop 

 of liquid exuding from one of them. 



The inquiry into the viviparous reproduction of 

 unfertilised aphids was afterwards pursued by Reaumur, 

 but soon handed over to Charles Bonnet (infra, 

 pp. 284, 286). 



Hive-hee 



Leeuwenhoek gives a very fair set of figures of the 

 sting of the bee, and also of the mouth-parts, though in 

 the latter case the bases are not shown.^ 



Fleas'- 



Leeuwenhoek hatched the eggs of fleas, saw the larvoe 

 curled up within them and afterwards observed their 



1 Phil. Trans. Noh. 94 and 97 (1673). 



^Arc. Nat. (1680, Epist. 76, 1693). Vol. II, pp. 20, 324-343. 



