324 BRENTHIDJE. 



[LeContc. 



developed to such an extent as to conceal the ligula and labial palpi. Of the 

 genera known to me Cylas is the only one in which the maxilla? are ex- 

 posed by the mentum not filling completely the buccal cavity, though other 

 cases are mentioned by Lacordaire. 



But what is most curious, is that while the mandibles of the 9 preserve 

 the pincer-form seen in many Curculionidce, and the beak is slender, and 

 in some species extremely long, for the purpose of performing its function 

 as an accessory organ of generation,* in the $ the mandibles assume a flat, 

 curved, and pointed form, resembling those of ordinary Coleoptera. This 

 sexual character is exhibited even in those genera in which the beak of the 

 tf is nearly as slender, and the moulh as small as in the 9 . 



The explanation of this difference in the mandibular structure is afforded 

 by the interesting remarks of Mr. A. R. Wallace, concerning the wonder- 

 ful pugnacity of the tf tf when in proximity to the $ . An excellent ac- 

 count of the assistance given by the $ to the 9 when she is occupied in 

 boring the hole in which the egg is placed, is also given by C. V. Riley,f 

 from observations made by his correspondent W. R. Howard, of Forsyth, 

 Missouri. 



These combats, however, result in no injury to either of the parties en- 

 gaged; the dense chitinous covering affords a perfect protection; the 

 weaker male, overcome by exhaustion, eventually flees, and leaves to his 

 more vigorous victor the honorable task of guarding and assisting the fair 

 objec of strife in her efforts to preserve the species. 



The habits, therefore, of these insects, as well as their peculiarities of 

 struc ure, deserve a closer attention than has yet been given to them. 



The smooth eyes, the reticulations of which are seen only through the 

 transparent integument, and the form of the front tibia?, indicate a resem- 

 blance, though a remote one, to Rhyssodidm. such as might perhaps exist 

 among objects of quite different nature originating in the same period of 

 time. The geographical distribution of the Brenthidw is also favorable to 

 the idea that they represent a tolerably ancient form of life. 



Tha 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 subfamilies, the characters 

 of which have been sufficiently exposed above. 



Antennae 11-jointed, last joint oval, pointed, not larger, BBENTHID^J. 

 Antennae 10-jointed; last joint very .elongate, CYLADID^. 



* Harris, Ins. Inj. Veg. 3d ed.CS; Wallace, Malay Archipelago (ed. Harper), p. 

 482; Kiley, Sixth Annual Report, Ins. of Missouri, p. 115. These authors men- 

 tion that the 9 makes with her beak deep perforations in the tree, and deposits 

 an egg in each one of them ; Lee., Am. Journ. Sc. and Arts, 1867. 



f Sixth Annual Report on the Noxious, Ac., Insects of Missouri, 1874, p. 415. 



