Chap. X. 
COLEOPTEltA. 
383 
sexual character in some few Coleoptera. Mr. Crotch 
has discovered that the males alone of two species of 
Heliopathes (Tenebrionidse) possess stridnlating organs. 
I examined five males of U. giblus, 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 
m the male. In H. crilratostriaius 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 line 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. gnjphus and nasicornis the ribs on the rasp of the 
pfo-pvgidium are less continuous and loss distinct than 
m 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 
°r are represented by excessively line down in the males. 
It should be noticed that in all Coleoptera the effective 
Part of the rasp is destitute of hairs. In 0. senagal- 
e >isis the difference between the sexes is more strongly 
parked, and this is best seen when the proper segment 
ls cleaned and viewed as a transparent object. In the 
female the whole surface is covered with little separate 
Cl 'ests, bearing spines ; whilst in the male these crests 
