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 E^aumur, 

 but soon handed over to Charles Bonnet (infra, 

 pp. 284, 286). 



Hive-bee 



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 larvae 

 curled up within them and afterwards observed their 



^Phil. Trans. Nos. 94 and 97 (1673). 



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



