BRENTHIDAE. 501 



of guarding and assisting tlie fair object of strife in her efforts to 

 preserve the species. 



The habits, therefore, of these insects, as well as their peculi- 

 arities of structure, deserve a closer attention than has yet been 

 given to them. 



The smooth eyes, the reticulations of which are seen only 

 tlirongh the transparent integument, and the form of the front 

 tibijB, indicate a resemblance, though a remote one, to Rhysso- 

 didai, such as might perhaps exist among objects of quite different 

 nature originating in the same period of time. The geographical 

 distribution of the Brenthidce is also favorable to the idea that 

 they represent a tolerably ancient form of life. 



The great extension of the longitudinal axis of the body exceeds 

 in some members of this family any proportion that occurs in 

 other Coleoptera ; and it is singular to see that a character, which 

 usually indicates feebleness of development, is here associated with 

 densely chitinized integuments, and great complication of domestic 

 life. 



The family divides itself naturally into two sub-families, the 

 characters of which have been sufficiently exposed above. 



Antenn?e 11-joiiited, last joint oval, pointed, not larger. BKENTHixyi:. 



Antennae 10-jointed, last joint very elongate. CyladinvE. 



Sub-Family I.— BRENTHIX.E. 



Of this sub-family two genera belong in the faunal limits treated 

 of in this work, though one of thorn (Brenthus), is in a political 

 sense partly extra-limital, having occurred in Lower California. 



These two genera represent in the arrangement of Lacordaire 

 separate groups, but in the plan of subordination of characters 

 herein adopted, they seem to indicate what we have called tribes, 

 wliich may be distinguished by the sexual and other differences 

 in the head, as well as by the form of the prothorax. 



Beak very dissimilar in the two sexes ; antennae not very remote from" tlie 

 eyes, rather slender, not compressed, nor clavate ; prothorax convex, 

 not grooved. Akkhenodini. 



Beak slender in both sexes ; antennae far distant from the eyes, somewliat 

 thickened and stouter externally ; prothorax deeply grooved towards 

 the base. Bukstuim. 



