284 CANAEIAN COLEOPTERA. 



In their gigantic size the present Acalles and the following one 

 differ widely from the other species enumerated. Inter se, however, 

 they are very nearly related ; nevertheless the arglllosus is perhaps, 

 on the average, a little larger than the ceonii, and the scales with 

 which it is thickly clothed are altogether of a paler, or more silvery, 

 hue ; its rostrum (at any rate of the females) is a trifle shorter and 

 straighter, more densely squamose posteriorly, less perceptibly incised 

 on either side at its extreme base (though this is partly due to the 

 scales being more numerous in that region), and in both sexes less 

 deeply sculptiu'ed ; its prothorax is rather less narrowed behind ; 

 its elytra (which have their immense punctures more evidently 

 arranged in longitudinal strioe) have their extreme apex (although 

 equally constricted) less regularly roimded, or somewhat more obtuse 

 and subbisinuate ; its tarsi are, if anything, a little shorter and 

 broader ; and its tibial hook is a trifle shorter and more acute. 



Hitherto the A. arglllosus has been observed only in TeneriflTe, 

 Avhere I obtained several examples, during May of 185'J, at Taga- 

 nana. It is an insect of eminently musical powers, being able to 

 create a loud jarring noise by the friction of the inner apical portion 

 of its elytra (which is roughened, or reticulated) against the setose 

 surface of its pygidium. Indeed this curious capability (which ap- 

 pears, however, to exist, more or less, in all the members of the 

 present genus, as well as in certain other* Curculionids) formed the 

 subject of a short Paper which I contributed to the ' Ann. of Nat. 

 Hist.' in July 1860. In fact the specimens were actually discovered 

 on account of this very fact, by my Portuguese attendant, who, 

 while shaking the hollow stem of a maritime shrub, was diverted by 

 a concert of no less than eleven musicians within ! And it would 

 consequently appear (since additional examples moreover were in 

 the pupa state) that the creature undergoes its transformations 

 within the branches of that particular plant, whatsoever it may have 

 been, and which, from the description given me at the time, I con- 

 cluded was probably the Kleinia neriifolia, DC. And that this con- 

 clusion was correct seems now pretty evident, since, on examining 

 M. BruUe's figure of his Tylodes scaber (for his " description," so 

 called, is positively worthless, and applies equally to the whole twelve 



* In my Paper above aUuded to, I described two large Plinfhi which are 

 similarly musical ; and Mr. F. Smith has tested the British species of Acalles, 

 and finds them to be gifted with a like power. Mr. Bewicke, who made most 

 careful observations in Madeira, heard the various Acalles of that island stridu'.ate 

 most audibly; and he has lately informed me that he has defected the same 

 noise in the Ccufharhi/nchus cckii. " which sings beautifully — working its pygi- 

 dium against the elytra, which are curiously thickened." 



