of the Amazon Valley. 215 



agreeing with Pteridotelus in other characters (e. g. A. maculi- 

 collis) ; others have the joints in question ciliated in the 6 and 

 at the same time elongated {A. lateralis) ; and many species 

 agree in the shape of the sterna, whilst resembling typical Acan- 

 thoderes in all other characters. I have thought it best on this 

 account to treat Pteridotelus as a subgenus or section of Acan- 

 thoderes. 



Acanthoderes and its allies (Steirastoma, Myoxinus, &c.) are 

 not, perhaps, so closely allied to the preceding genera as Poly- 

 r hap his ; it would therefore in some respects be better to place 

 the latter genus after AZgomorphus, followed by the Anisocerinae, 

 with which group it has also an evident connexion; whilst Acan- 

 thoderes leads through Alphus naturally to the Acanthocinitse. 

 This, however, would be presenting only one suite of affinities 

 amongst several which these insects present : the Acanthocinitse, 

 for instance, have a certain similarity to Or coder a and AUgomor- 

 phus. It seems almost hopeless to detect the true lines of affi- 

 nity, and quite so to represent them in a scheme of arrangement 

 when detected. 



§ 1 . Antennae with the terminal joints filiform, slender. 

 a. Fore tihise widely dilated and compressed. 



1. Acanthoderes hebes, n. sp. 



A. oblongus, convexiusculus, postice rotundatus, supra tomento fusco, 

 subtus pilis griseis sparsim vestitus : thorace tuberibus lateralibus 

 obtusis, dorsalibus tribus magnis : elytris apicibus parum trun- 

 catis, fuscis, fascia abbreviata pone medium nigra velutina, prope 

 apicem ochreo maculatis. Long. 5 lin. <$ $ . 



Head and thorax sooty-brown, with deep scattered punctures. 

 Antennae about the length of the body, black ; base of each joint 

 (from the third) and centre of the third with a pale testaceous 

 ring. Thorax with the lateral tubercles obtuse ; three dorsal 

 ones — two anterior very large and prominent, and one posterior 

 smaller and acute. Elytra rounded at the sides, towards the 

 apex very briefly truncated, with a short, tuberculated, longitu- 

 dinal, slightly elevated ridge in the middle of each near the base; 

 punctured throughout, the punctures accompanied by granulations 

 towards the base : the ochreous spots near the apex are few and 

 irregular. Under surface shining black, with a scanty grey pile. 

 Legs shining black, middle of the tibiae on the edge, tips of same, 

 and basal joints of the tarsi above greyish ; tarsi beneath yellow, 

 claw-joint pallid. In thee? the fore tarsi are black beneath, and 

 densely fringed with black hairs. The fore tibiae are abruptly 

 dilated from the middle in the 6 , more gradually so in the ? . 



On boughs of dead trees in the forest, Ega. Rare. 



