of the Amazons Valley. 309 



the middle, punctured (except near the apex) and marked with 

 an impressed stria near the suture ; colour rusty ochreous, with 

 a broad common brown vitta over the suture from the base to 

 beyond the middle, and a broad irregular brown fascia (lineated 

 with rusty brown) at the termination of the vitta, the space 

 near the apex having an irregular ochreous spot followed by a 

 similarly shaped brown spot. Body beneath light brown; sides 

 of prothorax and breast with an ochreous-white vitta; abdomen 

 streaked with ochreous white. Legs clothed with pale tawny- 

 brown pile. 



Found on a slender dead branch of a tree in the forests of the 

 Tapajos. 



Genus Ectho3a, Pascoe. 



Pascoe, Trans. Eat. Soc. n. s. iv. p. 244 (1858). 



Syn. Talasius, Buquet, Thorns. Arcana Naturae, p. 99 (1859). 



This remarkable genus is distinguished from the allied groups 

 by many well-marked features, which have been well described 

 by the authors above quoted. I myself met with female exam- 

 ples only, and have not been able to examine the opposite sex, 

 which bears one of the chief marks of the genus — namely, four 

 horn-like projections from the forehead. The body is large and 

 cylindrical ; the head very broad, and remarkable (besides the 

 horned forehead of the male) for the great convexity of the crown, 

 which rises very much higher than the base of the antennae, and 

 descends perpendicularly from its front edge towards the tuber- 

 cles which support those organs. The elytra are broad and 

 square at the apex, and each one is deeply sinuated in the mid- 

 dle, so as to form two projections or lobes. The antennae are 

 rather slender, in the female as long as the body, with the basal 

 joint tumid on one side at the apex, and the third joint slightly 

 curved. 



My specimens differ in colour from the one figured by M. 

 Buquet; but I believe them to be referable to the E. quadri- 

 cornis of Olivier. The Trachysomus faunus of Erichson (Consp. 

 Peru. p. 148) seems to be quite a distinct species of this genus. 



Ecthosa quadricornis, Olivier. 



Cerambyx quadricornis, Oliv. Ent. iv. p. 97, pi. 20. f. 158. 



Talasius quadricornis, Buquet, Thorns. Arc. Nat. p. 100, pi. 5. f. 6. 



The female example now in my collection, and which I found 

 at Ega, is 9£ lines in length, the head being 2| lines in width. 

 The upper part of the forehead is yellow, brown near the crown, 

 where it is marked with three black spots; the lower part is of 

 a blackish olive-colour, the line of demarcation between the two 

 colours being a transverse carina, from which in the male rise 

 the two lower frontal horns. The thorax is very uneven on each 



