72 SILPHID A. 
Fam. SILPHIDZ *. 
The Silphide of Central America, to judge from the present collection, appear to be 
remarkable for the rarity of forms usually the most abundant, such as the tribes 
‘Cholevina’ and ‘Silphina’; and for the peculiar type of the ‘ Anisotomina,’ which 
exhibit a great prevalence of species anatomically allied to Agathidium. The most 
abundant of these latter belong to the genus Aglyptus, first characterized by Dr. Leconte 
from a species of rare occurrence in the United States. In Central America Aglyptus 
seems to be the representative genus of its tribe, and numerically furnishes the majority 
of specimens contained in this collection. 
In this Family I have not given any Synoptic Tables, because the genera, with but 
few exceptions, are already well known, and for the most part contain respectively but 
few species, which may easily be discriminated from each other. The descriptions, 
especially of the new genera and species, will be found more diffusive than was perhaps 
positively required in a work which does not in any way assume the character of a 
monograph ; but it is always better in describing to say too much than too little, for 
among closely-allied species a minute and apparently unimportant character will often 
lead to a correct determination. The plan of devoting a separate sentence to each 
main division of the body renders recognition very much easier than the chaotic 
descriptions often met with, in which the various parts are so mixed up, that it becomes 
difficult to discover to which of them the words under consideration refer ; in many 
such descriptions characters of the head or thorax, omitted in their proper place, are 
often found noticed after a long description of the elytra, or some other part. 
In the anatomy I have always designated the extreme organ of the lower part of the 
mouth the “lingua”; the term “ligula,” often applied to this part having been used 
so indiscriminately for this organ, or for the labium, or for them both in connection, 
that it has lost all definitive value, and has, in fact, become a source of perplexity. 
That the lingua is a distinct organ of the mouth may be clearly seen in any of the 
larger species of Silpha, in all of which it is largely developed ; it arises from the inner 
side of the labium near to its base, and may easily be dissected from that organ. Indeed 
the parts often supposed to be paraglossal appendages of the labium are, at least in the 
genus Silpha, integral parts of the lingua, and are probably so in many other genera. 
The substance of the lingua is generally soft and contractile, and therefore liable, when 
dried, to lose its natural shape; but in St/pha the lingua is more than usually chitinous, 
and may always be seen behind the labial palpi as a somewhat fan-shaped organ 
extending far beyond the anterior extremity and the sides of the labium. 
* By A. Marruews. 
