Mr. T. V. Wollaston on certain Musical Curculionidse. 17 



and that, when the insect is alarmed, it is in a state of constant 

 and most rapid vibration. Now, whilst the under surface of this 

 abdominal apex is merely clothed with scales, the upper surface 

 (or pygidium) is destitute of scales, but slightly rough, deeply 

 punctured, and setose ; and the inner portion of the elytra (cor- 

 responding with the constricted, or suddenly -attenuated, apical 

 region, as seen from above), against which the pygidium comes 

 in contact at each of the pulsatory movements, is, to the naked 

 eye, merely dull and subopake (instead of being glossy, like the 

 rest of the inner tegument of the elytra) ; but when viewed be- 

 neath the microscope, this duller portion is coarsely shagreened, 

 or, more strictly, perhaps, minutely and very densely subreticu- 

 late : and I conceive that it is by the play of the bristles of the 

 pygidium against this subreticulated portion of the inner surface 

 of the elytra (assisted, perhaps, by the setse at the apex of the 

 dorsal apical segment, which comes in contact with the inner 

 surface of the ventral apical segment, which is likewise reticulate) 

 that the music is generated. 



In the gigantic Acalles Neptunus from the Salvages (an old 

 specimen of which I have just destroyed, in order to ascertain 

 whether it also possesses a similar stridulating instrument), the 

 reticulations of the inner surface of this constricted apical portion 

 of the elytra are much more elongate, appearing, at first sight, 

 almost like the ridges of the mesothoracic file of Deucalion-, 

 nevertheless, when viewed beneath a high magnifying power, 

 they are perceived (no less than those of the A. argillosus) to be 

 true reticulations, or meshes, being more or less irregular in 

 their formation, and made up of obliquely-transverse, as well 

 as longitudinal lines. I should therefore conclude, from the 

 large size of the insect and the comparative coarseness of its 

 subanal apparatus, that it is, in all probability, a species of great 

 musical capabilities. 



Whether all the Acalles have this remarkable power, I will 

 not undertake to pronounce ; but so far as the numerous repre- 

 sentatives from the Atlantic islands are concerned, I have but 

 little hesitation, from the general appearance of the constricted 

 apical region of their elytra, in believing that they have. And, 

 indeed, this conjecture has been absolutely verified in five of the 

 Madeiran ones by the direct and careful observations of Mr. 

 Bewicke, from whom I have received some very interesting re- 

 marks concerning them. On my arrival at Funchal, from Tene- 

 riffe, in June 1859, I exhibited my specimens (then in a lively 

 state) of the A. argillosus to Mr. Bewicke, and requested him to 

 listen attentively to the Madeiran species, whenever he chanced 

 to meet with them, during the following summer, in order to 

 ascertain whether or not they had a similar stridulating propen- 



Ann. $ Mag. N. Hist. Ser. 3. Vol. vi. 2 



