OOGENESIS IN PHILOSAMIA 11 
within the capsule. The strings open into a single slightly 
expanded chamber at the surface of the ovary, from which the 
oviduct arises. The earliest eggs are found near the opposite 
end of the ovary. Oogonial stages to very early eggs were found 
in this and similar ovaries. Figure 30 is of a January ovary, 
showing an increase in size and the growth of the egg strings. 
Two strings are broken away from the oviduct, but their points 
of attachment may be seen. The stages in this ovary ranged 
from a few spiremes to well-developed eggs, each with its five 
nurse cells contained in a separate chamber in the string. The 
ovaries of early June were practically identical in size with those 
of January. All the cells by this time have differentiated into 
eggs and nurse cells. In early July, the ovaries are markedly 
different. Figure 31 shows portions of three egg strings from a 
pupa about three days before the time of emergence. The ovary 
now consists entirely of egg strings with a decidedly beaded ap- 
pearance due to the growth of the eggs. 
b. Karly stages in the development of the ovary 
A description is given below of the stages in the development 
of the eggs and nurse cells from the oogonia to the first meta- 
phase of the egg. 
Stage a (fig. 37 a): The oogonial region containing cells in 
various stages of final oogonial divisions and in rest before these 
‘divisions. A polar view (fig. 2) of a metaphase plate shows 
26 chromosomes. In anaphase stages no lagging chromosomes 
were observed, nor differential divisions, such as have been 
described in several insects (Buchner ’09, Giinthert 710). 
Stage b (fig. 36): Post-oogonial nuclei. Here the chromatin 
assumes the form of deep-staining bodies with ragged and irreg- 
ular outlines. No constant number can be counted. The cells 
are connected by dense protoplasmic strands or tubes, which 
appear to originate from the spindle remains of the oogonial 
divisions. Giimthert (10) figured similar connections between 
eggs and nurse cells in the oogonia of Dytiscus. In figures 41 
and 42 are shown two tubes with their branches appearing to 
terminate in rounded: knobs, which are merely the upturned. 
