STEUCTUEE AND BIOLOGY OF SCHIZONEUEA LANIGEEA. 671 
YI. The Inteenal Anatomy. 
The internal anatomy of Schizoneura lanigera, so far 
as I am aware, has not been studied in any detail before. 
Indeed, considering the great economic importance of the 
Aphididte, our knowledge of the anatomy of this family is 
very small. Several of the earlier workers on aphids, such 
as Dufour (1833), Morren (1836), Kaltenbach (1843) and 
Buckton (1875-82), treated in a g'eneral way of the anatomy 
of the group. Later, Balbiani (1866, etc.), Mark (1877), 
Witlaczil (1882, 1884), and Will (1888), have done much to 
further our knowledge of the internal structure and histology 
of these important insects. Of more recent contributions 
to the literature of aphid anatomy, the works of Dreyfus 
(1889 and 1884), Ki’assilstschik (1892-3) on Phylloxera 
vastatrix, Mordwilko (1895) on the anatomy of Trama 
and Lachnus, Flogel (1904) on Aphis ribis and Grove 
(1909) on Siphonophora rosarum may be cited. 
Distribution of the Internal Organs. 
When the dorsal integument is carefully removed under 
normal salt solution from a living, apterous viviparous female 
of S. lanigera, as shown in fig. 5, numerous olive-coloured 
fat body cells are seen, lying beneath which are a number of 
oval yellowish-brown embryos (e.), in various stages of 
development. These embryos are contained in long, thin- 
walled tubes or the ovarian caeca {p. c.), which are trans- 
versely constricted along their length to form several 
large ovarian chambers, in which the embryos are borne. The 
crnca are arranged in two groups, one group on each side of 
the median line, with about four or five crnca in each, and 
extend throughout the greater part of the body. In the 
posterior region of the abdomen the tubes from each side 
lead into a wide oviduct (ocZ.), and the two oviducts enter 
into a median, muscular chamber, the vagina {v.), which 
leads to the genital orifice. 
