258 C. T. BRUES, 
At this point there is a wide gap for which I cannot find inter- 
mediate stages in my material. 
There is a single later stage which was found in a female of 
another species (X. nigrescens) but which does not in all probability 
differ from the corresponding stage in X. peckü. 
In these eggs the appendages of the embryo are already formed 
and give it the appearance of a typical generalized insect embryo. 
Due to the small size and almost spherical shape of the egg, the 
embryo is folded in a peculiar way in order to accommodate itself to 
the cavity of the egg. As usual the ventral surface of the embryo 
is directed towards the chorion, but the embryo is too long to permit 
of its longitudinal axis simply following a meridian of the egg, and 
at the base of the eighth abdominal segment the abdomen is sharply 
flexed to the right at an angle of 90 degrees. The thick envelopes 
of the eggs make it difficult to get good surface stains of such embryos, 
and as the eggs are too small to allow of the embryos being dissected 
out, I have been compelled to make Fig. 19 and 21 somewhat 
diagrammatic and to omit the finer details. A few points about the 
appendages of the embryo seem worthy of notice. The antennae are 
very small compared to the mandibles, being even smaller than the 
first and second maxillae, and the abdominal appendages, although 
quite distinct on all the basal segments, are considerably longer on 
the first. The small size on the antennal rudiments at this early 
stage may be correlated with the absence of antennae in the adult 
female, although the adult male has very highly developed antennae. 
The central mass of yolk is separated into five or six nearly equal 
masses each containing a single large yolk cell. 
There is in all embryos in this stage a large, flattened cell which 
is entirely external to the embryonic body, resembling a large oenocyte 
in appearance, which is usually placed between one side of the head 
and the chorion. Several of these peculiar cells are shown in Fig. 20, 
Their function may possibly be better elucidated when older embryos 
are examined, but from their position it would seem that they may 
be in some way associated with the formation of the secondary yolk 
or with some other phenomenon of nutrition. 
Following this stage there is another gap, as there are no older 
embryos in the material at hand. 
