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 Acaii- 

 thoderes. 



Acanthoderes and its allies {Steirastoma, Myoxinxis, &c.) are 

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

 rhaphis; it would therefore in some respects be better to place 

 the latter genus after JEgomorphus, followed by the Anisocerinse, 

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

 thoderes leads through Alphus naturally to the Acanthocinitae. 

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

 amongst several which these insects present : the Acanthocinitae, 

 for instance, have a certain similarity to Oreodera and jEgomor- 

 pkus. 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 tibiae 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 trua- 

 catis, fiiscis, fascia abbre\"iata pone medium nigra velutina, prope 

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



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 the d 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 $ . 



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



