Ptinida. of the Canary Islands. 193 



which 1 am anything but certain should not in reality be regarded 

 as the whole mentum (for, when mounted in balsam, it is seen to 

 be separated from the transverse basal-piece by a distinct articu- 

 lative line), is an immense, central, narrow, subtriangular, or 

 rather mitriform, corneous organ, widest at (or just before) its 

 base, and gradually attenuated to its apex, where it is more or 

 less obtuse. This monstrous organ (which has usually been over- 

 looked !) rests upon (and fits into the centre of) a broader trans- 

 verse base (closely soldered to the jugulum) which has frequently 

 been treated as the entire mentum : but, as just stated, I am not 

 altogether satisfied that it should be taken as a part of the men- 

 tum at all, seeing that it is more separated from the above-men- 

 tioned mitriform process than it is from the jugulum. At all 

 events, in dissection, it is very difficult to split-ofF this wide trans- 

 verse basal portion in anything like a definite shape ; sometimes 

 it conies away with elongated acute anterior angles, whilst at 

 others it breaks-ofF(even in the same species) leaving no angles 

 at all, and yet with equal symmetry. At any rate its exact outline 

 (with reference to its lateral angles and breadth) is so extremely 

 doubtful, that I think it cannot safely be employed as affording 

 any character of generic importance.* The ligula (which must 

 next be noticed) is always long and narrow, and more than half of 

 it is concealed behind the mitriform process of the mentum ; but 

 it is slightly rounded, divergent, and pilose, towards its apex, — 

 at only a short distance from which the palpi are implanted. 



Such, then, are the instrumenta cibaria of the Ptinidce. The 

 only other structural feature which would seem to be very con- 

 stant throughout the family is the more or less close approximation 

 of the antennae-}" (which have their second joint short, and the 



* I perceive, since the above was written, that IM. Jacq. Duval, in his recent 

 enunciation of the family-characlerislics of the Ptinid-e, has absolutely omitted 

 all mention of (and therefore rejected) this transverse basal-piece as forming a 

 part of the mentum [ — " Menton corne, grand, plus ou moins fortement triangu- 

 laire, entier"] ; but this possibly may be regarded as somewhat rash, for it is at 

 least as doubful whether it be a portion of the jugulum as ii is whether it belongs 

 to the mentum. Still, as above slated, I am inclined to think (more particularly 

 from the uncertainty of its shape) that it would be better perhaps to leave it unno- 

 ticed when describing tlie several menta. 



t There are one or two exceptions, however, even to this. Hedobia is one of 

 them; and M. Duval states that the true Trigonogenii from Chili (which are 

 generically distinct from the Mediterranean and Atlantic species) have their an- 

 tennas widely separated at the base. Also my Ptinus nigrescens and frugilis, 

 from Madeira, possess the same character (the latter accompanied by a rather 

 conspicuous biarticulated club), and will probably require eventually (at any rate 

 the P.fragiUs) an additional genus for their reception. 



VOL. I. THIRD SERIES, PART II. MAY, 1862. O 



