THE WEEKLY ENTOMOLOGIST. 
101 
its legs against the edge of its elytra. 
There are, already, nearly a dozen 
species known. 
Genus Pseudoxycheila. 
Elytra proportionately narrower at 
the base than in the last genus. 
The typical species (P. iipustulata ) 
* * * * is one of the most beautiful 
of the family. It has been for some 
time very rare in collections, but of 
late years a great number of speci- 
mens have arrived from Columbia. * 
« * if 
Genus Teteacha. 
* * * * Elytra of the breadth of 
the prothorax. * * * * !S T o wings. 
* * * * The three first joints of the 
anterior tarsi, strongly dilated in the 
males. * * * * 
This genus consists of large apter- 
ous insects, of robust form, and of a 
brilliant metallic green color, more 
or less vivid, and often inclining to 
blue. Only three species are now 
known, — peculiar to Africa. 
Genus Teteacha. 
* * * * Elytra almost always 
having their humeral angles distinct, 
owing to the presence of the inferior 
wings. * * * * Appearance much 
less robust than in the former genus. 
The species are numerous, and, 
with the exception of a very small 
number inhabiting the old world, are 
found in America. They are divided 
into two groups, — those of the one 
(and they form by far the greater 
part) are, like those of the old world, 
green or blueish, and have, in gen- 
eral, a testaceous spot, at the tip of 
each of the elvtra ; — those of the other 
are testaceous or reddish, with ill de- 
fined brown or black blotches. * * 
* * The Tetrachce are nocturnal 
insects. * * * * 
Genus Aniaea. 
This genus differs from Tetracha in 
the following points, — * * * * An- 
tennae shorter, more robust, and 
filiform. The three first joints of the 
anterior tarsi of the males less atten- 
uated at their base, and less obliquely 
sculptured at their ends. 
Only one species is known (A. 
Sepulcralis ) from Cayenne. It is of 
a slightly metallic black color, with 
the elytra covered with punctures, 
and with irregular slightly raised 
ridges. * * * * 
Thus we close our notice of the 
Tribe Megacephalides. As it and the 
preceding tribes are of small extent 
we have been able to give a fuller 
summary of M. Lacordaire’s observa- 
tions than will be possible where the 
tribes are larger. Next week the 
tribe Ctcindelides will come under 
review, and as it is of much greater 
extent than either of the two latter 
we shall be compelled to give a very 
bare abstract indeed. 
THE MUTABILITY OE SPECIES 
OR RACE EORMS. 
Continued . 
“ It must be very far back in point 
of time, although perhaps geologically 
speaking of recent date, that the 
Atlantic was so far bridged over, as 
that the individuals of any race of in- 
