1H81.] COLEOPTERA FROM ECUADOR. 265 



20. Alurnus saundersii, Baly, Cat. Brit. Mus. p. 28. 



A specimen brought by Mr. Buckley appears to be referable to 

 this species, but has a black spot on the shoulder, which is not men- 

 tioned in the description. 



Hab. Ecuador. 



21. Alurnus mutabilis, n. sp. (Plate XXX. fig. 3.) 

 Niger, suhopacus, thoracis lateribus elytris(j_ue pallide flavis, his 



plus minusve nigro ornatis. 



Long. 9-10 lin. 



Thorax one quarter broader than long, moderately convex, very 

 sliglitiy narrower in frunt than behind, very gently arcuate at the 

 sides ; not very strongly, but rather thickly and irregularly punc- 

 tured ; yellow, with the disk and tlie extremely fine lateral margin 

 black ; there is a sudden constriction in front at the extreme anterior 

 margin ; and there is a small incision at each posterior angle. 

 Scutellum smooth, impressed. Elytra dull, pale yellow," parallel at 

 the sides, arcuately acuminate at the apex ; very thickly but ob- 

 scurely punctured ; the extreme apical margin and the suture 

 black, the black more or less dilating at the scutellum ; the apex is 

 rather acutely produced and is not emarginate. The black marks 

 on the elytra vary : there appears always to be a black spot on the 

 shoulder ; this spot sometimes extends itself obliquely towards the 

 suture, and sometimes expands so much as to unite with the black 

 at the scutellum ; there is also frequently a spot behind the middle 

 of each elytron, sometimes forming a large black patch. 



Most nearly allied to A. lansbergi, Salle, but less elongate. 



22. Alurnus cassideus, Westw. Ann. Nat. Hist. 1841, viii. 

 p. 204. 



Two examples with entirely black elytra. Specimens brought by 

 Mr. Buckley, in a former collection, have the elytra more or less 

 rusty yellow, in which they agree more nearly with the original type. 

 The type of this species is said to come from Mexico, and, according 

 to a sketch in Prof. Westwood's possession, is much broader in the 

 elytra than the specimens from Ecuador. As, however, there seems 

 to be some doubt as to the correctness of the locality given for the 

 type, and as the specimens from Ecuador vary somewhat in form, I 

 think it best at present to consider them all one species. 



23. Arescus labiattjs, Perty, Del. Anim. p. 101, pi. 20. f. 7. 

 Hab. Sarayac\i ; Ega, Nauta, St. Paulo. 



24. Arescus perplexus, Baly. (Plate XXX. fig. 14.) 



This species differs from A. lahiatus in having the antennae black, 

 with the basal joints pale beneath ; the basal joint has the projection 

 obliquely truncate, so that it is obtuse instead of being acute; the 

 thorax is rather more deflexed at the anterior angles, and has a slight 

 impression at the base before the scutellum. Tlie interantennal 

 process of the forehead is rather short and broad, truncate in the 



Proc. Zool. Soc— 1881, No. XVIII. 18 



