Chap. X. COLEOPTERA. 383 



sexual character in some few Coleoptera. Mr. Crotch 

 has discovered that the males alone of two species of 

 Heliopathes (Tenebrionidse) possess striclulating organs. 

 I examined five males of H. gibhus, 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. cribratostriatus 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. gryplius 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 



