■Chap. X. 
CfOLEOPTERA. 
383 
sexual character in some few Coleoptera. Mr. Crotch 
has cliscoyered that the males alone of two species of 
Tlcliopathes (Tenebrionidse) possess stimulating organs. 
I examined five males of H. gibbus , and in all these 
there was a well-developed rasp, partially divided into 
two, on the dorsal surface of the terminal abdominal 
segment ; whilst in the same number of females there 
was not even a rudiment of the rasp, the membrane of 
this segment being transparent and much thinner than 
in the male. In H. cribrcdostriatus the male has a 
similar rasp, excepting that it is not partially divided 
into two portions, and the female is completely desti- 
tute of this organ; but in addition the male has on 
the apical margins of the elytra, on each side of the 
suture, three or four short longitudinal ridges, which 
are crossed by extremely fine ribs, parallel to and re- 
sembling those on the abdominal rasp ; whether these 
ridges serve as an independent rasp, or as a scraper 
for the abdominal rasp, I could not decide : the female 
exhibits no trace of this latter structure. 
Again, in three species of the Lamellicorn genus 
Oryctes, we have a nearly parallel case. In the females 
of 0. gryphus and nasicornis the ribs on the rasp of the 
pro-pygidium are less continuous and less distinct than 
in the males ; but the chief difference is that the whole 
upper surface of this segment, when held in the proper 
light, is seen to be clothed with hairs, which are absent 
or are represented by excessively fine down in the males. 
It should be noticed that in all Coleoptera the effective 
part of the rasp is destitute of hairs. In 0. Senegal - 
ensis the difference between the sexes is more strongly 
marked, and this is best seen when the proper segment 
is cleaned and viewed as a transparent object. In the 
female the whole surface is covered with little separate 
crests, bearing spines ; whilst in the male these crests 
