BALBIANI. 
67 
More recently Balbiani'^ has given us elaborate and 
illustrated papers, full of microscopic detail, which 
bear on the reproductive anatomy of Aphis. His 
first memoir contains an excellent account of the 
divided opinions and varied theories of most of the 
investigators who preceded him. But one chief feature 
of his recorded observations is connected with the 
revival of the old idea, started originally by Leuwen- 
hoek, that the apterous and winged viviparous females 
are hermaphrodite, and that these individuals are 
capable of self-impregnation.f As in his former treatise, 
he describes at length the male Aphis and its pro- 
gressive development from birth to maturity, so in his 
later memoir, written in 1870,J he examines the struc- 
ture and use of the different organs of the oviparous 
female, and sets forth the origin of the ovum and the 
changes which take place in it after its^fecundation. 
He states that all his predecessors had missed the 
precise characteristics of reproduction in the oviparous 
female of Aphis. Anatomists had asserted that 
Aphides^ in their dioecious character, differed in no 
fundamental particular from insects known to belong 
to the same class, and that in them existed the same 
general plan of the reproductive organs ; further, that 
in both cases similar elements were elaborated from 
them. At the commencement of his third memoir 
Balbiani states, in opposition to generally received 
views, It is sufficient for me to say beforehand that, 
in showing the facts of a perfectly characterised sexual 
dioeciousness, these facts interweave themselves with 
circumstances which insuperably bring to mind some 
of the intimate phenomena of the propagation of vivi- 
parous Aphides, and that this mixed character discovers 
itself even in the organisation of their respective 
Balbiani, “ Sur la Beproduction et I’Embryogenie des Pucerons,” 
‘ Comp. Bendus,’ t, Ixii, 1866. 
t Balbiani, “ Memoire snr la Generation des Aphides,” ‘ Ann. des 
Sciences Naturelles,’ 15 ser., t. xi, 1869. 
X Balbiani, ‘ Bibliotbeque des Hantes Etudes,’ Memoires sur la 
Generation des Aphides,” Paris, 1870. 
