724 THE GENERATIVE ORGANS. 
menon in 1871, with some observations communicated to me 
by the late distinguished Coleopterist, Dr. J. A. Power. 
The early maturation of the sperm may be termed Protandry, 
and compared to the analogous condition in hermaphrodite 
plants. Protandry is widely spread amongst hermaphrodite in- 
vertebrates, and the early transference of the sperm to the female 
organism in Insects is perhaps an indication of an hermaphro- 
dite ancestral condition. The protandrous condition of Insects 
does not appear to have attracted the attention which this re- 
markable phenomenon deserves. 
If one may venture to generalise, it appears to me probable 
that the existence of spermathece in the developed female is 
connected with this protandrous condition. In the Lepidop- 
tera, in which it does not exist, I have sought in vain for sper- 
mathece; their place is probably taken by the large bursa, 
which is connected with the oviduct by the spermatic canal, 
and, so far as I can judge, those who have described sper- 
mathecz in these Insects have mistaken other structures for 
them. They certainly exhibit nothing like the spermathece of 
the Diptera and Hymenoptera. 
The single so-called spermatheca of the Cockroach—Peri- 
planeta orientalis—is evidently a bursa similar to the bursa of 
the Lepidoptera. 
In the Diptera, as has been already stated, there is no bursa 
properly so called, and it appears probable that this organ is 
represented by the uterus, in which the ova in some genera are 
normally retained until the embryo is fully developed, or even 
until the larva is ready to pass into the pupa stage. 
5. THE EXTERNAL GENERATIVE ORGANS. 
a. General Considerations and Nomenclature of the Abdominal 
Segments. 
Although in some Insects the external generative organs are 
exceedingly simple, in others their complexity is very great ; yet 
no definite nomenclature has been established by which the 
