98 
Proceedings of Royal Society of Edinhurgh. 
On the Reproductive Organs of Noctua pronuba. By 
A. B. Griffiths, Ph.D., F.E.S. (Edin.), &c. (With a Plate). 
(Read June 6, 1892.) 
The Insecta are dioecious Invertebrates, and the rudiments of the 
sexual organs exist in the larvae, but are chiefly developed during 
the pupal stage. These organs present such wide and manifold 
variations, that even those of individuals belonging to the same 
genus are so widely different in structure, &c., that it is only by a 
systematic study of each species that the student of nature is capable 
of arriving at correct conclusions concerning the reproductive organs 
of any particular species. 
In the present paper the author gives an account of the repro- 
ductive organs of Noctua pronuha (Linnaeus) ; as there has been no 
account given of these organs in this species, or even in this genus. 
The abdomen of both sexes consists of nine segments or somites, 
and in a state of rest the posterior two are retracted within the 
seventh segment ; the intersegmental membranes in each case being 
long enough to admit of a telescopic action. 
The Male Organ and its Appendages. 
The dorsal portion of the ninth segment of the male is produced 
backwards into a slightly curved hook (fig. 6, a). This hook covers 
the anal aperture, and in some Noctuidse, as well as other Lepi- 
doptera, is greatly developed. The ventral portion of the same 
segment forms a broad trough-shaped process (fig. 6, &), with up- 
turned lateral edges, the penis (figs. 6 and 7, c) lying in the bottom 
of the trough so formed, and fastened to each side of the same 
segment are the claspers (fig. 6, dd')^ which are narrow triangular 
pieces, each having a slightly incurved apex. There are two pro- 
trusible sac-like organs (fig. 6, cc), which are also attached to the 
ninth segment, at the base of the claspers. These organs have 
delicate membraneous walls covered with long hair-like scales, 
which give each of them the appearance of a brush. Each organ 
may be protruded or retracted at will. The internal lining of these 
