133 
Generally distributed throughout the Amazons region, on both 
sides of the river. It is found on slender branches of fallen 
trees in the forest. The terminal segment of the abdomen of 
the female is scarcely visible beyond the tips of the elytra. 
Genus Toron^us, nov. gen. 
Body oblong, somewhat convex. Head and thorax of nearly 
equal breadth, and much narrower than the elytra. Antennae 
greatly elongated ; joints long and slender, sparingly furnished 
with setae both above and beneath. Thorax with a slight pro- 
tuberance on the sides a little behind the middle, in place of the 
lateral spines. Elytra without setae, and free from ridges and 
lateral carinae. Terminal segment of the abdomen in the males 
with both dorsal and ventral plates more or less notched at the 
tip. Ovipositor of the females greatly elongated, and generally 
exserted beyond its sheath, tubular ; dorsal plate of the terminal 
abdominal segment (constituting the sheath) slender and pointed, 
ventral deeply cleft at the apex. Legs moderately slender ; 
thighs clavate; tarsi undilated and simple in both sexes; basal 
joint of posterior tarsi as long as, or longer than, the three suc- 
ceeding taken together. 
This genus is distinguished from all the preceding by the 
cleft or deeply notched apex of the terminal ventral segment in 
the females; in this it agrees with Graphisurus of Kirby*, 
which, again, is connected by intermediate species with Acantho- 
cinuSf a group containing the well-known A. cedilis, or carpenter- 
beetle, an. inhabitant of the wooded parts of our own island. 
Thus all the numerous genera of Acanthocinitse are closely linked 
together ; for species of Nyssodrys (e. g. N. signifera) exhibit to 
a slight extent the character of a cleft apex of the terminal ven- 
tral segment, and this genus leads on without any sharp line of 
demarcation to Leiopus^ — showing that the European genera 
Leiopus and Acanthocinus, which appear to us so far asunder, 
are connected together by insensible gradations of form. The 
typical species of Toronceus (namely those which have no thoracic 
spines) are easily distinguishable from Graphisurus ; but if the 
bounds of the genus be extended a little, so as to embrace a few 
* This genus comprehends the following North- American species : — 
1. G.fasciatus, De Geer, Mem. v. p. 114, t. 14. f. 7- 
, Kirby, Fauna Boreali-Americana, Ins. p. 169, 
?= Lamia mixta, Fabr. E. S, Suppl. 144. 26. 
2. G. ohsoletus, Oliv. Col. iv. p. 130, t. 13. f. 90. 
= Astynomus Icevicollis, Dj. Cat. 
3. G. pusillus, Kirby, Fauna Bor.-Araericana, p. 169. 
Acanthocinus aiomarius (F.), of Europe, is also probably a Graphisurus. 
