34 
apical ventral segment, the ? having in that part a deeply im- 
pressed fovea. The genus was established on certain curious 
species which agreed in having greatly elongated and hair-like 
antennae, and strongly bowed fore tibiae. I have extended the 
definition so as to embrace the Alphus Lacordairei of Dejean^s 
catalogue — an insect which difiers from all other Alphi, including 
A. tuber osus of Germar, to which it has otherwise some resem- 
blance, in the curiously abrupt dilatation of the first antennal 
joint — a feature characteristic of the genus yEthomerus. jE. La- 
cordairei jdifiers from the other species in having straight fore 
tibiae, and in having rather less elongated antennae, whose arti- 
culations are much shorter in the $ than in the S . 
The species are nocturnal in their habits. They are of rare 
occurrence, and are found in the daytime crouched on leaves, — 
Lacordairei^ however, being seen only closely adhering to 
deeayed boughs. In those species which have strongly bowed 
fore tibiae, the anterior femora are greatly enlarged and furnished 
on the inner side with a sharp ridge, which fits a corresponding 
groove along the tibiae. In the crouching position, the fore legs 
are closely folded, the almost invisible antenuae laid backwards, 
and the whole insect assumes a rigid aspect, well calculated to 
deceive its enemies. Lacordairei, on the other hand, possesses 
passive means of defence of quite a different character : its co- 
lours and markings give it a deceptive resemblance to a dead 
pupa eovered with a fungous growth, such as is often seen ad- 
hering to trees in damp climates. The deception is perfect, the 
insect having on each side of its body a large spot coloured and 
reticulated like a wing seen through the integument of a pupa. 
Thus we see here another instance of the widely different means 
Nature employs, within the same genus, to maintain the exist- 
ence of her specific forms. Every species exists by virtue of 
some endowment which enables it to triumph over the infinite 
diversity of adverse circumstances that surround it at all stages 
of its life. This concerns us here, inasmuch as the general 
principle has an important bearing upon the systematic arrange- 
ment of species, a knowledge of the fact that structures are 
adapted to the ends just mentioned being necessary to avoid 
errors in estimating their affinities. Longicornes are greatly 
subject to these adaptations, those parts of structure being mo- 
dified, from species to species, on which we depend for the esta- 
blishment of genera, thus rendering, in this family, real generic 
definitions almost impossible. 
I. jEthomerus antennator, Fabricius. 
Lamia antennator. Fab. Syst. Eleuth. ii. p. 288. 36. 
E. elongatus, tenuiter tomentosus, niger vel brunneus, variegatus : 
