Anatomy of the Male Genital Tube in Coleoptera. 603 
Our limited material did not show us the development 
of the male parts; but in the imago there are nine distinct 
tergites and eight distinct sternites, the ninth sternite ap- 
pearing to be represented by a Y-shaped sclerite (fig. 234). 
A large amount of dechitinisation has apparently taken 
place at the apex of the abdomen, as well as at the base, 
and it is possible that some part of the large membranes 
at the apex (z.¢. at the base of the genital tube) may 
represent sternites. 
We divide the genital tube into the following parts. 
A pair of seminal ducts leading from the testes forms the 
zygotic portion (fig. 239 a—b), and the long, single, highly 
irregular tube, folded back and joined to the ‘body wall, 
forms the azygotic portion (fig. 239 b-d, 5-1). The 
paired, or zygotic portion (a—b), along with certain glands 
opening into it, is considered to be of mesodermic origin,* 
and the azygotic, along with certain glands, of ectodermic 
origin. Bordas t points out that very little is known as 
to the origin of these glands, and consequently objects to 
the terms ectadenia and mesodenia applied to them by 
Escherich, and calls them accessory, or annexed glands. 
We are not concerned with them here. 
The first part of the azygotic portion of the genital tube 
(fig. 239 b-c) consists of a long, more or less slender, tube 
(the stenazygotic portion) ; beyond this the tube enlarges 
and forms the eurazygotic portion (c-d and 5-1). In many 
cases this enlargement of the azygotic portion of the tube 
takes piace before it is reflected outwards to continue its 
course to join the body wall. We call that portion of the 
eurazygos that is usually not external (c—d), the “internal 
sac”’ (“sac interne” of Jeannel). 
In all cases that we have observed the internal sac is 
evaginated during copulation, and forms a continuation 
of the external parts of the genital tube. In a great 
number of forms there is no demarcation between the 
stenazygotic and the eurazygotic portions of the tube 
before the outward reflection above mentioned ; in such 
cases we say that the internal sac is undifferentiated. 
That portion of the tube that is reflected and thus forms 
the external portion of the organ we call phallic. But we 
* On this subject see Escherich, Zeitschr. wiss. Zool. lvii, 1893, 
p- 620. 
{ Bordas, Ann. Soc. Ent. France, Ixviii, 1899, p. 510. 
