DESCRIPTION 09 PLATE l>. 



/> and c represent other pseudova, in which the mass 

 has undergone a coarse segmentation : d, the fourth 

 chamber, in whicli the pseudovitellus shows a partial 

 differentiation ; e, the fifth chamber or ovisac, in 

 which may be seen indications of a body-cavity (s) 

 forming out of the blastodermic layer (j>) ; /, the last 

 pseudovarian chamber, in which the embryo has become 

 more advanced ; p, part of the procephalic lobe of the 

 blastoderm ; ?/, yolk-mass or pseudovitellus ; r, rudi- 

 mentary fold of the abdomen ; o, rudiments of the 

 foetal pseudovum, which occurs thus early in these 

 insects. Mag. 112 diam. 



The details of this sixth chamber are after Prof. 

 Huxley, but an error occurs in my present figure as 

 to the position of the head, which, as before said, 

 should have been turned in the opposite direction. 



Both Huxley and Brandt have noted exceedingly 

 line ligaments proceeding from the free ends of the 

 apical chambers of the pseudovaria. Such ligaments 

 have not been observed, I believe, in the organs of the 

 true female. These pseudovarian ligaments would 

 seem to have some free intercommunication with the 

 corresponding tubes (?) of the cajca situated at the 

 other side of the Aphis. Their omission in this figure 

 does not argue their absence in the living insect. 

 (Fide Huxley, 1. c, p. 199.) 



Fig. 3. — Similar parts of the ovigerous tube of 

 Ghermes abietis. These ovisacs are very numerous, 

 and number more than one hundred. The peculiar 

 cord observed and described by Huxley in " Vacwna 

 dryophila" (Callvpt&rUS quercus?) is here readily seen 

 at h. This cord is better seen in Plate V. 



Pig. 4. — The forceps-like appendage at the tail of 

 Ohermes la/rids, employed by the insect in arranging 

 her eggs. Both figures = 52 diameters. 



Pig. : ».— Much magnified apical chamber of Myzus 

 i>< rsiar, showing several large nucleated cells or clear 

 vesicles, as al /and at//. These consist of periplastic 



and endoplastic layers. One of these at a time de- 



