9 
is, however, an error, the eredit of pointing out which is due 
to M. Thomson in his recent work on the Cerambycides. A 
deep depression around the base of the tubercle seems to have 
given rise to the mistake ; but in fact the depression, which is 
found also in great numbers of Lamiaires, is not continuous, as 
a slight examination will show. 
1. A. longimanuSj Linn, and authors. 
The Amazonian examples of this insect are smaller than those 
found in other parts of South America. It is not a very com- 
mon insect, and is not found, as its great size would lead one 
to suppose, on the larger trees of the forest ; I have found it 
almost always on slender boughs, or on tree trunks of moderate 
dimensions. I have sometimes cut the insect out of the rather 
hard wood of such trees, near the centre of which it passes the 
larva and pupa states. The stridulation of the species is very 
loud, and can be heard at many yards^ distance in the forest. 
It appears not to be confined to one kind of tree ; I have found 
it on the Inga, a genus of Leguminosse, and on the Jabuti-puhe, 
a wild fruit-tree of the order Anonacese, as well as other trees. 
On the Inga it is sometimes seen in company with Oreodera 
glaucay — the Oreodera being coloured in close imitation of the 
bark, and clinging very closely and flatly to it, thus eluding 
observation, whilst A. longimanus in its bright colours forms 
a very conspicuous object. It is very slow in motion, but has 
the habit of bending its long legs rigidly in self-defence on 
being disturbed. Thus, of two allied species, one has the means 
of defence and maintenance of existence in one way, and one 
in another. 
2. A. trochlearisy Linn. 
Cerarnhyx trochlearis, Linn. Syst. Nat. ii. 622. 
Frionus trochlearis, Oliv, Col. iv. 7* 13. 49. 
This elegant species seems to be peculiar to Guiana and the 
Amazon region. Its habits are similar to those of A. longi- 
manuSy in so far as it is found on the moderate-sized branches 
of frees blown down in the forest. 
The allied A. accentifer I did not meet with ; it is found in 
S.E. Brazil and in Venezuela, but not in the intermediate 
country of Amazonia. 
Genus Oreodera. 
Serville, Ann. Soc. Ent. Er. iv. 19. 
The body in this, as in the preceding genus, is elongated and 
flattened ; the species, however, are of much smaller size. The 
prothorax has on its disk three prominent tubercles, arranged in 
c 
