1958 ] Woodland — Thermobia domestica (Packard) 17 
each of which is bent and coiled upon itself many times. 
The contents of the living, freshly laid egg appear to 
consist of colorless yolk spheres in a colorless liquid of low 
viscosity. The spheres are about 10 to 15 microns in 
diameter. In sections of eggs fixed with Maximow’s fluid 
the negative images of the fat spheres measure 9 or 10 
microns in diameter. Most of the more numerous, visible, 
proteinaceous yolk globules are 14 or 15 microns in diameter. 
Some of these globules appear structureless, while others 
appear finely granular. The globules appear only very slight- 
ly flattened at the poles with Maximow’s fixative. The other 
fixatives used always badly distorted the yolk of young 
eggs. The yolk spheres and liquid fill the entire egg. Cyto- 
plasm was not identified. 
Perrot (1933) stated that the first maturation division 
occurs while the oocyte is still in the ovariole. He was not 
able to find any trace of the prophase of the division. He 
reported that the mitotic figure occupies a very small space 
at the periphery of the oocyte and figured the anaphase of 
the division. He stated further that after this first matura- 
tion division the nucleus enters a resting stage which he 
figured from a freshly laid egg. The present study did not 
confirm this part of Perrot’s work. The only mitotic figures 
ever found in sections through the vitellarium were those 
of the follicle cells. The anaphase of such follicular mitoses 
often resembles that shown in the first of Perrot’s figures 
just mentioned. Eggs fixed immediately after oviposition 
show the nucleus to be in the metaphase of the first matura- 
tion division. No nucleus resembling both in appearance and 
position that shown in the second of Perrot’s figures was 
found until the beginning of the formation of the primary 
epithelium. 
The anastral type of meiosis occurs. The mitotic figure is 
located more or less equidistant from the two poles of the 
egg, usually from 1 to 10 microns from the surface. The 
spindle axis is usually oblique to the egg surface, but is 
occasionally parallel to it. The distance between the two 
poles of the mitotic figure in metaphase and in anaphase 
(Fig. 2) is about 20 microns. The metaphase plate is about 
8 microns in diameter. The chromosomes are very small 
