Chap. X. 
COLEOPTEEA. 
379 
ribs are scraped by the posterior margins of the elytra, a 
small portion of which projects beyond the general out- 
line. In many Crioceridse, and in Clythra 4 - punctata 
Fig. 24. Necropkorus (from Landois). r. The two rasps. Left-hand figure, part of 
the rasp highly magnified. 
(one of the Chrysomelidm), and in some Tenebrionidse, 
&c., 70 the rasp is seated on the dorsal apex of the abdo- 
men, on the pygidium or pro-pygidium, and is scraped 
as above by the elytra. In Heterocerns, which belongs 
to another family, the rasps are placed on the sides of 
the first abdominal segment, and are scraped by ridges 
on the femora. 71 In certain Ourculionidae and Cara- 
bidae, 72 the parts are completely reversed in position. 
70 I am greatly indebted to Mr. G. K. Crotch for having sent me 
numerous prepared specimens of various beetles belonging to these three 
families and others, as well as for valuable information of all kinds. He 
believes that the power of stridulation in the Clythra has not been pre- 
viously observed. I am also much indebted to Mr. E. W. Janson, for 
information and specimens. I may add that my son, Mr. F. Darwin, 
finds that Dermestes murinns stridulates, but he searched in vain for the 
apparatus. Scolytus has lately been described by Mr. Algen as a stri- 
dulator, in the 1 Edinburgh Monthly Magazine/ 1869, Nov., p. 130. 
71 Schiddte, translated in * Annals and Mag. of Nat. Hist.’ vol. xx. 
1867, p. 37. 
72 Westring has described (Kroyer, 1 Naturhist. Tidskrift/ B. ii. 1848- 
49, p. 334) the stridulating organs in these two, as well as in other 
families. In the Carabidse I have examined Elaplirm uliginosus and 
Blethisa multipunctata , sent to me by Mr. Crotch. In Blethisa the 
transverse ridges on the furrowed border of the abdominal segment do 
not come into play, as far as I could judge, in scraping the rasps on the 
elytra.; 
