68 ON THE AGAMIC REPRODUCTION AND MORPHOLOGY OF APHIS 
The whole larva is covered by a continuation of the delicate 
membrane already noticed on the limbs and abdomen. The blasto- 
derm invests the abdomen almost completely, but in front it covers 
only a somewhat fiddle-shaped area on one face of the yelk. It is 
still more deeply bilobed in front, and the antennules and antenne 
are much elongated. The larva next begins to grow, being doubtless 
nourished by the fluid contained in the maternal pouch; and at the 
same time its ventral region assumes a curve, contrary to that which 
it originally possessed, becoming more and more convex. 
The cephalic region is now clearly distinguishable; it occupies 
nearly one-half of the whole length of the body. The procephalic 
lobes extend upwards over the anterior face of the vitellus, and upon 
each a large rounded elevation, the rudiment of the ophthalmic 
peduncle, has made its appearance in front of the antennule. The 
latter, like the antenne, elongate greatly, and become divided longi- 
tudinally, within the sheath afforded by the primitive integument, 
into their two terminal branches. 
A slight constriction indicates the boundary between the anten- 
nulary and antennary sterna, and behind these, similar depressions 
mark off the surface of the blastoderm into seventeen additional 
segments. 
Attached to them are as many pairs of appendages, which in the 
youngest larvae: examined had the following form :— 
The first pair were rounded massive elevations, situated one on 
each side of the pit indicating the position of the oral aperture ; from 
their anterior edge a short oval palp already projects. These are the 
rudimentary mandibles. 
The next pair, or first maxilla, are small rounded elevations 
meeting in the middle line. The second maxilla succeed, and are 
more elongated, three-jointed, and bent back parallel with one an- 
other. The maxillipedes and the thoracic ambulatory legs form one 
continuous series of similar appendages, all elongated and bent back 
against the sternal surface of the body. 
The abdomen is very short, but is clearly distinguishable from the 
thorax by its less complete segmentation, and by the rudimentary 
condition of all its appendages save the last pair. 
The blastoderm as yet extends only for a little way on the sides 
of the body. The primitive larval integument still invests the whole 
body loosely, but passes smoothly over all the appendages, except the 
antennules and antenne, which continue to be ensheathed by it. 
The larva remains in this general condition until it attains zrth of 
an inch in length, the principal differences in its later stages being the 
