1892 - 93 .] Mr A. B. Griffiths on Organs of Noctitapronuba. 99 
organs is an epithelium which secretes a fluid, for these organs are 
protruded by being filled with this fluid. This odoriferous fluid * * * § 
finds its way outwards by the “ hairs ” which thereby become 
excretory ducts. It is probable that these appendages are “ scent 
organs ; ” at all events there can he little doubt that they are organs 
for sexual excitation. They are entirely absent in the female, and, 
consequently, these organs act as an allurement to the female. 
The male organ of reproduction consists of a large testis, two 
vasa deferentia, in each of which a tubular gland opens, a ductus 
ejaculatorius, and a penis. The kidney-shaped testis (fig. 6, /), 
which is pigmented,! is composed of two glands which have 
fused together during the metamorphosis. These glands are distinct 
in the larva, and lie close under the dorsal vessel in the fifth abdo- 
minal segment.! 
The vasa deferentia (fig. 6, g) lead from the posterior face of the 
testis. After a few convolutions they dilate into two curiously- 
shaped chambers, from which proceed two long capillary prostates 
(fig. 6, 7i), which ultimately unite with the mucous glands (fig. 6, 7), 
into the basal portion of which the vasa deferentia seem to open. 
The vasa deferentia ultimately unite into a long and convoluted 
ductus ejaculatorius (fig. 6, 7:), which contracts slightly near its end, 
but again dilates into a muscular portion, which opens into the 
penis. 
The penis is a slender, chitinous tube § whose tip projects between 
the claspers and beloAV the anal aperture j and, as already stated, it 
lies in the trough formed by the ventral arch of the ninth segment. 
It is protruded by a muscle on either side which is attached to the 
same segment. From the terminal portion of the penis project two 
bifid hooks (fig. 8), which bear on the inner side several spines or 
teeth. These hooks appear capable, to a certain extent, of pro- 
* Smelling of vanilla. 
+ This pigment appears to be one of the lipockromes. 
Z In certain Lepidoptera, the distinct condition of the testes is retained in 
the i7nagines. 
§ The supporting substance in this organ is chitin, as was proved by its 
insolubility in solutions of sodium hydroxide, and its solubility in strong 
hydrochloric acid. After prolonged boiling with HCl, followed by evaporation, 
minute crystals of glucosamine hydrochloride were produced. 
