576 Mr. D. Sharp and Mr. F. Muir on the Comparative 
broad median struts, and from the base proceed two long, flattened 
supports (a) that connect it to the lateral lobes. No differentiated 
internal sac. 
Aesalus scarabaecoides. 
Has a long, tubular median lobe, slightly curved; median 
orifice at distal end and median foramen at base. Tegmen con- 
sisting of a small ring-shaped basal-piece with narrow (almost 
hair-like) lateral lobes about two-thirds as long as the median 
lobe, and closely appressed thereto; these are all amalgamated 
at base and show no articulation. Internal sac not observed. 
This distinct form is worthy of more investigation. We have had 
only one example at our disposal. 
Nicagus obscurus. 
Since our paper was written Mr. Schwarz has kindly 
given F, Muir an opportunity of dissecting this problem- 
atic form, and he finds that it isa Lucanid, not a Scarabaeid. 
The description and remarks on its affinities must be 
published elsewhere. 
Sinodendron cylindricum (Pl. XLII figs. 9 and 92). 
The median lobe is small, curved, tubular and highly chitinised ; 
the median orifice at the distal end; the median foramen, a long 
narrow opening along the ventral basal aspect; a pair of large 
median struts are articulated to the base; the point of articulation 
has a dorso-basal position. The lateral lobes are small, concave 
across the inner side (a) where the median lobe lies. The basal piece 
forms a large, strongly chitinised tube. The internal sac undifferen- 
tiated, the basal part (b) is always protruding from the median 
orifice. 
In the Lucanidae there are several types of aedeagus, 
but they all differ from the Scarabaeidae in having a well- 
developed chitinous, exposed median lobe, and the internal 
sac is never developed to so great an extent as in the 
Scarabaeidae, unless we consider the flagellum as a modi- 
fied sac. In that case the sac in the forms of the two 
families may be said to be very different. 
In our taxonomical table we have suggested a division 
of Lucanidae into three families, Lucanidae, Lamprimidae 
and Sinodendronidae. This seems necessary if Trogidae 
are separated from Lucanidae. The alternative is to unite 
the five divisions, Trogidae, Scarabaeidae, Lucanidae, 
Lamprimidae and Sinodendronidae into a single family. 
