122 
THE ORDER, OF COLEOPTERA. 
only a moderate quantity of combinations. From this it results that 
the groups superior to genera can be characterized in a few words, and 
their limits are, in general, sufficiently well defined. With the Tenebri- 
onidte, on the contrary, an instability without limit is the rule ; not a 
single organ, even the most insignificant, escapes. If, as we ought, we 
take all of them into account, the number of combinations to which they 
give rise is so great that it is impossible to bring any of them to the 
front, and for each group we are obliged to pass in review almost the 
entire organization. If to this we add the insensible transitions between 
the forms of organs which are themselves equally unstable, we shall 
understand how the groups thus constituted absolutely refuse to admit 
of any precise definition.” Yol. V, p. 289. 
But, notwithstanding the difficulty of dividing this tribe into minor 
groups by any sharp lines of demarkation — a difficulty which we are 
continually encountering, in a greater or less degree, in .all our attempts 
at generalization in natural history — they may still be arranged in sev- 
eral divisions which will facilitate the determination of species. Thus 
regarded, this tribe will constitute the family of Tenebrionidie, which 
can be divided into several minor groups which will take the rank of 
sub-families. 
Family LIII. TENEBRIONIDIE. 
This family having been already sufficiently described in treating of 
the tribe which it constitutes, w-e proceed to designate the sub family 
into which it may be divided : 
A. Antenna; longer than the head and thorax united, slender and of nearly or quite 
the same width throughout; front separated from the labrum by a membra- 
nous clypeus ; body often with a metallic or brassy tint IIkloptdes. 
A A. Antenna- usually about as long as the head and thorax united; gradually en- 
larging towards the tip, and with the joints usually more or less round or 
moniliform; front articulating directly with the labrum ; color black: 
Tenebkionides. 
AAA. Antenna; usually shorter than the head and thorax united, with joints wider 
than they are long, or more or less perfoliate; middle coxa; without tro- 
chantins; color generally brown I'lomides. 
Sub-family 11ELOPIDES. 
The name Helops appears to have been originally given to a harmless 
species of serpent, but was appropriated by Fabricius to a sub-division 
of the coleopterous genus Tenebrio, of Linn mus. We use the family 
name here in a comprehensive way to include a considerable number ot 
species distinguished from the Teuebriouidse proper by the characters 
given in the foregoing table. The larvte resemble those ot Tenebrio, 
