Beetles of British Guiana. 
short transverse thorax tapering to a sharp point at each 
side. Its wing-cases are nearly triangular, and ending 
the thorax form an acute point at the basal angle. There 
is also a perforation at the base of each of the elytra 
from which the insecl: receives the specific name of 
perforata. 
The Cassida lucluosa, another of our beetles, is a small 
roundish inse6l, nearly black on the upper side, but 
reddish towards the edges of the wing-cases and below. 
It has a short thorax running into very acute angles at 
the sides. 
The Cassida sexpustula, which is sometimes found 
here, is nearly circular in exterior outline, and is green 
above, and black below. 
The Cassida discoides is a green beetle with large 
yellow spots running across the middle of its elytra. 
These are some of the better known Cassidae met with in 
this part of the world, but a number of other species 
are found here. 
We have also several beetles of what is called the 
Eumolpus family. The word eumolpus means " good- 
singer," and is a very strange name to give to a voice- 
less beetle, for it neither gives us any idea of the appear- 
ance of the inse6l nor of its habits. It is also a proper 
classical name. These beetles do not differ very much 
from the Cassidae, and are sometimes classed with them. 
The Doryphora (from the Greek doru, a spear or 
spike, and phero, I carry) or spike-bearing beetles are 
easily distinguished from their kindred genera. If one 
looks at a specimen from above he sees no spike or 
spear, but if he looks at the thorax or breast below he at 
once perceives that the middle of it projects in a sharp 
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