THE PRIMITIVE WEEVILS. 19 



iujury. The small one, however, soon ran away, acknowledging 

 himself vanquished. In most <Y>leoptera the female is larger 

 than the male and it is interesting, therefore, as bearing on the 

 question of sexual selection, that in this case, as in the stag 

 beetles where the males tight together, they should be not only 

 better armed but also much larger than the females." Riley has 

 also recorded (1874, 115) that it takes about a day for the female 

 of En])#(i1is niiniitd to make a puncture and deposit an egg, the 

 male meanwhile standing guard and occasionally assisting his 

 mate in extracting her beak. Should a strange male happen by 

 a furious contest at once ensues, and continues sometimes for 

 hours, until one or the other is thrown from the tree. The suc- 

 cessful party then takes his station as guard and, if it be the 

 stranger, takes the same care of the female as did the vanquished 

 rival. 



The family Brenthidse is represented in North America, as 

 far as known, by only seven species distributed among six genera. 

 These have been treated by LeConte & Horn in their Rhyncho- 

 phora of North America, and in part by 



Horn, Geo. #. "The Brenthida? of the United States," in 



Trans. Am. Ent. Soc., IV, 1872, 127121). 

 tfclHrffcr, ('has. "Table of Genera and Species of N. Amer. 



Brenthidae," in Journ. N. Y. Eut. Soc., XXIII, 1915, 52- 



55. 



KEY TO EASTERN GENERA OF NORTH AMERICAN 15RENTII11XE. 



a. Antennas 11-jointed, the last joint oval, pointed, not much longer than 



the others. 



It. Head short, transverse or quadrate, hardly prolonged and not con- 

 vergent behind the eyes; beak of female equal in length to that of 

 male or longer. 



c. Antennal joints 2 11 equal in width, or the outer slightly nar- 

 rower; beak very dissimilar in the two sexes, shorter and broad- 

 er in male, narrow and cylindrical in female; thorax without 

 median groove. I. EUFSALIS. 



cc. Antennal joints 2 8 equal in width or nearly so, the last three 

 broader, forming a feeble club; beak nearly alike in the sexes; 

 thorax with a strong median lengthwise groove. 



II. TRACIIKUZUS. 



l)l>. Head longer than broad, oval, prolonged and convergent behind the 

 eyes; beak of female shorter than that of male; thorax deeply 

 grooved near base. III. BRENTHUS. 



aa. Antennas 10-jointed, the last joint very elongate; form somewhat ant- 

 like; antennae inserted near middle of beak. IV. CVLAS. 



