42 
Mr. H. W. Bates on 
angustato^ apice late rotundato^ angulo suturali 
spinoso ; supra opaca^ subtiliter alutacea^ cinnamoiiea^ 
absque lineis elevatis. Corpus subtus nitidum^ im- 
punctatum^ castaneum. Pedes nigro-castanei^ nitidi. 
Long. $ (mandib. in cl.) 28 lin. 
I am not aware that the male of this very rare species 
has been heretofore described. It differs greatly from 
the female in the punctuation of the thorax^ and in the 
size of the antero-lateral spine. A similar sexual differ- 
ence exists in M. flavipennis (Chevrolat) the female of 
which is named serridens in ChevrolaPs collection^, and 
in M. Dejeanii (Gory); the male in all these species 
having a finely punctured opaque thorax_, with a glossy 
space in the middle, and the female being uniformly 
scabrous-punctate, slightly shining. 
I met with one example only of M. crenata on the 
Amazons, near Ega. 
Genus Titanus. 
Serv. Ann. Soc. Ent. Fr. 1832, p. 133. 
1. Titanus giganteus. 
Linn. Mant. p. 531; Drury, 111. iii. p. 73, pi. 49. f. 1, ? . 
T. ( ^ , ? ) fusco-castaneus, thorace lateribus trispinosis, 
supra punctato-rugoso, medio late impunctato, tibiis 
intus multispinosis, $ l^vibus, antennis utroque 
sexu dimidium corporis baud excedentibus, seg- 
mento ultimo ventrali in medio late exciso, ^ 
integro. 
Long. 4^-6 unc. 
In addition to the sexual differences mentioned in this 
short diagnosis, may be mentioned the much greater 
width of the tarsi in the S' than in the $ . The tarsi of 
the $ are of remarkable width, and the second joint is 
transverse quadrangular, instead of triangular as in the 
$ and in Longicorns generally. On the Amazons this 
colossal Longicorn was found only near Manaos, on the 
Eio Hegro; where it is occasionally picked up on the 
shores of the river after a stormy night, the insect being- 
cast into the water whilst flying across.* 
* In the system of Lacordaire the group Ancistrotides follows the Tita- 
nides, but in a note on a subsequent page (Genera, viii. p. 163) he justly 
doubts whether they would not be better placed near the group Tragoso- 
mides. The following new species of Acanthinodera (group Ancistrotides) 
tends in favour of this emendation. 
