CURCULIONID^:. 273 



gifted with a like power ; and the late Mr. Bewicke heard no less 

 than. five of the Madeiran Acalles "sing" most distinctly. Future 

 observations will probably show that a large proportion of the 

 weevils are endowed with this capability ; for I myself called atten- 

 tion to two gigantic Canarian Plinthi which were able to stridulate, 

 and Mr. Bewicke detected a similar noise in the Ceutliorliynchus 

 echii " which (as he quaintly expressed it) sings beautifully, work- 

 ing its pygidium against the elytra, which are curiously thickened." 

 It is by the rapid vibration of the pygidium that the jarring is pro- 

 duced its setose upper surface being made to play, at each move- 

 ment, against the reticulated inner face of the elytra (the apical 

 portion of which, as well as in some instances the rim, is specially 

 roughened for this particular purpose). 



753. Aealles seonii. 



Acalles aeonii, Chcvrolat, in litt. 



, WolL, Cat. Can. Col. 285 (1864). 



, Deliarnv., Ann. de la Soc. Ent. de France, iv. 452 (1865). 



Habitat Canarienses (Ten., Gom.), intra caules Sempervivi occurrens. 



Likewise a Canarian Acalles, which has been observed hitherto in 

 Teneriffe and Gomera, and which appears to be attached to the dif- 

 ferent species of Sempervivum (some of which constitute the genus 

 ionium of Webb). In the latter of those islands the Messrs. Crotch 

 took it abundantly " from out of the great rosette-like Sempervivum 

 which everywhere studs the rocks;" and examples were communi- 

 cated to me from Paris by M. Chevrolat (who purchased them from 

 a French naturalist who formerly collected at Teneriffe), with a note 

 appended to them to the effect that they were captured within the 

 stalks of the " ^Eonium frutescens" Although in some respects the 

 A. ceonii and the argillosus (which infests the Kleinia neriifolia) are 

 closely allied, a fine series of both species, now before me, from the 

 recent material of the Messrs. Crotch, shows that they have much 

 less in common than I had originally supposed*. 



* The A. ceonii ranges smaller than the argillosus, and the scales with which 

 it is clothed are of a very much darker (or browner) tint ; its rostrum (in both 

 sexes) is a little longer and more deeply sculptured, as well as more naked pos- 

 teriorly (which causes it to appear more conspicuously incised on either side at 

 its extreme base) ; its prothorax is more rounded at the edges ; its elytra are 

 rather more pointed (or less obtusely bisinuated) at their apex, and have their 

 inequalities rather more abrupt and developed ; and its feet are longer. In the 

 numerous examples now before me, the <eonii varies in length from 2 to 4 

 lines, whilst the argillosus ranges from 3i to 5f . 



