122 THE OKDER OF COLEOPTERA. 



only a moderate quantity of combinations. From tliis 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- 

 ouidfe, on the contrary, an instability without limit is the rule ; not a 

 single organ, even the most insiguificaut, 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 InseMsible 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." Vol. V, p, 289. 



But, notwithstanding the difiiculty of dividing this tribe into minor 

 groups by any sharp lines of demarkation — a difiiculty 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 ElII. TENEBRIONID^. 



This family having been already sufficiently described in treating of 

 the tribe which it constitutes, we proceed to designate the sub-family 

 into which it may be divided : 



A. Antennse longer than tile 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 Helopides. 



A A. Antennte 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: 



Ticnkbrionidp:?. 



AAA. Autonnie usually shorter than the head and tluu-ax united, wilh joints wider 



than they are long, or more or less perfoliate; middle coxte without tro- 



chantins ; color generally brown Ulomides. 



Subfamily HELOPIDES. 



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 Liunjcus. We use the family 

 name here in a comprehensive way to include a considerable number of 

 species distinguished from the Tenebrioniche proper by the characters 

 given in the foregoing table. The larvue resemble those of Tenebrio, 



