292 
THE WEEKLY ENTOMOLOGIST. 
OBSERVATIONS. 
COLEOPTERA. 
The genus Pterostichus . — There is 
no genus in the whyle of the Goleop- 
tera which thrusts itself more on the 
attention of all than does that whose 
name heads this article. Its species 
abound in all sorts of places, from 
the wood or mountain to the cellar. 
Thus, there is probably no beginner 
in the study of beetles who has not 
got a good many specimens belong- 
ing to it, though very possibly he 
might feel puzzled as regards the 
number of species to which they 
belong. In writing the random 
series of articles I proposed in No. 
35, of the “ Entomologist” I do not 
think that any genus is better suited 
to occupy the first place than one of 
which all collectors possess repre- 
sentatives while its species are 
very closely allied. I therefore, shall 
attempt in the present article, to 
furnish a few useful hints on the 
habits, localities, and specific distinc- 
tions of the genus Pterostichus. 
The most favorable season of the 
year for collecting these beetles is 
Spring. They then abound under 
stones, logs of wood, and may often 
be observed hurrying along in the 
sunshine, or hiding in the obscurity 
of a damp cellar. As a rule they 
are not confined to one particular 
description of locality, though there 
are several exceptions to this. For 
instance, picimanus is not frequently 
met with away from a clay forma, 
tion, c ethiops inhabits mountainous 
districts, while gracilis and diligens 
are attached to low marshy ground. 
The g’enus as now determined in 
Waterhouse’s catalogue, unites many 
genera which previous authors re. 
garded as distinct. Stephens split 
it into 'nine, viz., Poecilus, Abax, 
Pterostichus , Platysma, Adelosia , 
Steropus, Omaseus, Argutor, Platyde- 
rus , while of the twenty- three species 
now considered as included in it he 
made about forty. 
Several neighbouring genera bear 
sufficient resemblance to the one 
under notice to puzzle beginners, and 
we cannot wonder if they even con- 
found it with those of other families, 
when we find that Stephens places 
Patrobus in the middle of Pterostichus. 
Space however forbids my exceeding 
the bounds of the genus in the pre- 
sent notice. I may observe that it 
can be distinguished from most of 
its neighbours by the shape of the 
thorax, which is much more elon- 
gated than in Amaru, Harpalus, &c., 
and much less contracted behind 
than in Anchomenus. It is remark- 
able that from the commencement of 
the Coleoptera down to the end of 
the Ilarpalidae, according to Water- 
house’s arrangement, the thorax, 
with few exceptions, assumes greater 
proportions in each successive genus. 
In Pterostichus eight species may 
be considered universally common, 
viz; cuprous, vers icolo, slriola, niger, 
