ON THE AGAMIC REPRODUCTION AND MORPHOLOGY OF APHIS 79 
DESCRIPTION OF THE PLATES. 
Tas. XXXVI. [PLATE 1]. 
Aphts Pelargonid. 
The letters have the same signification throughout. The fractions indicate the measured 
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size, in parts of an inch, of the objects. 
1. The three anterior chambers of a pseudovarium: a. the apical chamber; B. the 
second; c. the third. a. Pseudovarian ligament; 6. wall of the pseudovarium ; 
« its epithelium; @. periplast or homogeneous matrix of the apical chamber ; 
e. clear vesicle; f its endoplast, the two corresponding with the germinal vesicle 
and spot of an ovum; g. a pseudovum partially detached, its periplast greatly 
enlarged; e’. its vesicle, whose endoplast is invisible; 4. blastoderm ; 2. pseudo- 
vitellus. 
. 2. Terminal chamber of a pseudovarium, with the second chamber beginning to be 
formed in consequence of the enlargement of the pseudovum (g), which is about 
gtath of an inch in diameter. 
. 3. The pseudovum is still more enlarged, and the second chamber is nearly distinct. 
The vesicle, e’, remains, and exhibits certain indistinct granules in its contents. 
The cells of the blastoderm of c measure about 33459th of an inch in diameter. 
4. The second chamber is quite distinct from the first, and contains a mass (g) in which 
no clear vesicle could be discovered: this mass became clearer and irregularly 
areolate by the action of water. 
5. The cellular germ-mass. The cells or clear cavities have a diameter of about 
gvcth of an inch; their endoplasts are hardly more than zp$poth of an inch in 
diameter. 
Tas. XXXVII. [PLATE 2]. 
Aphis Pelargonit. Letters as before. 
1. A portion of the blastoderm and pseudovitellus of an unaltered germ, only y$gth of 
an inch in length, but otherwise like the preceding. The clear vesicles measured 
gzigsth of an inch; the endoplasts zg$acth. 
2. A germ extracted from its chamber and treated with acetic acid. It has no pseudo- 
vitelline membrane. 
3a. A germ extracted from its chamber. It is enclosed within a pseudovitelline mem- 
brane (4); and its pseudovitellus is arranged in obscure spheroids, of which one is 
represented in 3 J. acted on by water. Its granules are about s7pcth of an inch in 
diameter. 
4. Germ zi;th of an inch in length. The cells of the posterior end (3) present a sort of 
break (/), and the blastoderm on one side is greatly thickened. The thickened 
portion offers an indication of a division (z). The anterior end (y) is also somewhat 
thickened. 
5a. Germ z4pth of an inch, enclosed within its pseudovitelline membrane : #, rudiment 
of the abdomen ; v. of the thorax; g. of the head; /. gap corresponding with /, 
and now filled by the pseudovitellus; g. inner layer of the germs 7. that portion 
of it which will become the pseudovarium. 5 2. Diagrammatic view of the same, 
viewed from above. 
6. Lateral view of » larger germ without its pseudovitelline membrane. The anterior 
part of the cephalic blastoderm (f) has extended upwards, and constitutes the pro- 
cephalic lobe g’.. The rudiment of the pseudovarium (7) is still more distinct than 
in the preceding. 
