242 
Psyche 
[December 
2. The ruptor ovi, or egg bursters 
The newly hatched larva of Ancistrocerus antilope has defined sets 
of minute, fixed spines (0.8-9 /* long X 0.8-6 /x in diameter) on the 
dorso-lateral surfaces of the three thoracic segments and the first 
three abdominal segments (figs. 4-1 1). In each case these sets of 
spines are located anterior and very slightly dorsal to each corres- 
ponding spiracle, at or near the mid-length of its segment; the spines 
are not moveable, and their bases appear to be continuous with the 
cuticle. Unlike the general scatter of spines in the thoracic sets, 
nearly every spine of each field on the first three abdominal segments 
is at least partially coalesced with its neighbors. The massive, caudal- 
ly directed, hypertrophied, pale amber teeth thus formed on the sides 
of the anterior abdomen bear many smaller denticles and blade-like 
serrations that also point caudally (figs. 5-8). From the base of 
their most cephalad component spine to their caudal tip, these elon- 
gated, composite abdominal teeth are, on the average, some 60-80 /x 
long X 20-30/x at their widest. Each rises at an average angle of 
I2°-I5° (30° in an extreme instance) from its anterior origin on 
the lateral surface of the larva to a caudad peak that is some 14-18 /x 
high. 
The dentate fields of the three thoracic segments are more loosely 
organized, their spines and blade-like projections not coalescing into 
a single large structure. That on each side of thoracic segment- 1 
consists of 10-14 irregularly directed, stubby spines, and 4 or more 
blade-like ridges or denticles arrayed in a patch that is much wider 
(ca 30/x) than long (ca 22 /i) (fig. 9). The spinous sets on each side 
of thoracic segment-2 are also wider (ca 30 yx) than long (ca 18 jjl) , 
each possessing 7-10 small spines and four or more lamina-like denti- 
cles (fig. 10). As in the case of the sets on segment- 1, those on seg- 
ment-2 have their spines and denticles projecting in different 
directions, more or less haphazardly, and several spines and blades 
may appear coalesced. 
Each field of spines on thoracic segment-3 is much larger than 
those of segments- 1 and-2, differing also by being roughly triangular 
in shape, with the apex of the triangle pointing forward (fig. 1 1 ) - 
The wide base of this field lies caudad, roughly normal to the long 
axis of the larva, and approximately equal in length to the altitude 
(ica 60 and 55^ respectively). Individual spines are for the most 
part well spaced, numerous (ca 25-35), and directed caudally. In 
some larvae, however, 3 or more of the posterior denticles may be 
laminate and clustered, much as those of the first two thoracic fields. 
