104 
Wisconsin Academy of Sciences , Arts and Letters. 
its size to the development of extremely high ectoderm cells. No mesodern 
enters into the construction of the peculiar organ which in the later stages 
of development disappears entirely.” 
Cholodkovsky s paper [’89] which in respect of the pleuropodia of 
Blatia adds but little to Patten's description, appeared several months after 
my account of these organs was written. After describing the origin of 
the different appendages, the Russian observer passes to a more detailed 
description of the first abdominal pair. 
“ While the ectoderm cells keep increasing in length in the first abdom¬ 
inal appendages, those of its constricted basal portion, on the contrary, 
become somewhat shorter. As a consequence of these changes the abdom¬ 
inal appendage assumes the shape of a pear attached to the body by means 
of a slender stem only. The greater portion of such an appendage consists 
of very long and narrow, almost fusiform ectoderm cells, which with their 
broadening distal ends form the surface of the appendage, while their 
proximal ends narrow towards the peduncle. The cells are very closely ap¬ 
plied to one another, and there is no cavity in this portion of the modified 
appendage, though there is a narrow canal in the axis of the peduncle 
leading into the body cavity. Somewhat nearer its distal than proximal 
end each long ectoderm cell contains a large oval nucleus. Focussing on 
the surface of the widened portion of the pear-shaped body one observes 
that it is divided into facets; each facet has slightly raised edges and a 
central depression, and belongs to an ectoderm cell. During later develop¬ 
ment before the hatching of the embryo these appendages disappear by a 
process unknown to me.” 
This description is in the main correct. It is true that the outlines of 
the pleuropodial cells are polygonal in surface view, but I have never seen 
anything like the facets with raised edges and depressed centers described by 
Cholodkovsky and depicted in his Fig. 15 This appearance is probably due 
to Cholodkovsky's method of preparing Blatta embryos by protracted im¬ 
mersion in Perenyi’s fluid, a method which is in all probability responsible 
for the marked distortion of some of his other figures. 
Mantis. 
To Grdber we owe the only account of abdominal appendages in Mantis 
embryos published heretofore. In his general work on insects [‘77] he 
figures the anterior portion of a young Mantis embryo, in which the 
pleuropodia are seen as a pair of digitiform processes, directed and shaped 
like the thoracic legs, which they are far from equalling either in length or 
breadth. In his later paper ['88] Graber figures another embryo Mantis in 
which is seen a pair of what might be called secondary pleuropodia on the 
second abdominal segment. This second pair, wliich is absent in some em¬ 
bryos is somewhat smaller, though in other respects exactly like the first 
pair. Further stages in the development of these organs are not described. 
