AMERICAN COLEOPTERA. 



267 



served ia the Triplectrus group of Anisodactylus or the Trisena group 

 of Amara, The larger spur of the middle and posterior tibiae is 

 slender but abruptly wider from the middle to the base. This form 

 of spur is important in the determination of sex, as some species 

 have the anterior tarsi as slender in the male as in the female, so 

 that the presence of a permanent character common to all males 

 enables us at once to determine to which group a species should 

 be referred. 



The importance of sexual difl'erences in the male has always been 

 recognized as a means of fitly dividing the species in groups, by all 

 authors who have studied the genus, (Erichson, Kraatz, Tournier and 

 Thomson), the latter even going so far as to separate those with 

 anterior tarsi dilated and those not so into two genera. 



Recognizing the value of some independent characters for the 

 determination of sex, one which will be common to all the species 

 and not to a part only, M. Henri Tournier (Ann. Ent. Soc. Fr. 1863 

 p. 134), states that the males have five abdominal segments and the 

 females but four. He says : " I have been able to convince myself 

 that this character is constant, I have observed it in nature on all the 

 species of the genus with the exception of G. emarginatus Rosenh. 

 which I have not been able to procure." 



In a very careful examination of our species I am prepared to say 

 that this character has absolutely no value as far as they are concerned. 

 In support of my own assertion the following table is presented which 

 can be made instructive from another standpoint. 



