NORTH OF MEXICO. 



299 



the addition of other tribes the trouble is by no means lessened. In those tribes contain- 

 ing large scries of genera, the tendency to a rapid degradation of form is seen, analagous 

 to the same general degradation -of the entire family from the Tentyriidse to the Otido- 

 gense. Thus, among the genera of the tribe Tenebrionini forms occur pointing strongly 

 toward an affinity with TIelops, and it is here among what might be termed the peripher- 

 ial genera that doubt may arise as to their true position. 



The separation of the sub-family into Platygense and Otidogemc has not been followed, 

 as the character seems not to deserve the importance assigned to it by Lacordaire, and 

 Mr. Pascoe (Ann. and Mag. Nat. Hist., Ser. IV, Vol. Ill, p. 36,) objects to the placing 

 of the latter section among the Tonebrionid*, evidently not fully appreciating the fact 

 that this sub-family as defined by Leconte has a much greater systematic value than any 

 of the "Cohorts" of Lacordaire. 



A careful revision of foreign tribes, on the basis of the sub-division of the Family into 

 three- sub-families, would result in the union of several. From the limited amount of study 

 I have been able to give them, the Heleides appear to replace in Australia the Blaptini 

 of Europe and America, and should probably form a, sub-tribe of Blaptini, in which their 

 peculiar form would be fully balanced by our species of Embaphion. 



Many changes might be suggested, but as such discussion is altogether irrelevant to 

 the objects of the present paper, further space will not be occupied here, although it is my 

 desire at some future time to develop the results of study in a paper less encumbered with 

 species. 



The following table of tribes is offered for the assistance of the student, although well 

 aware that it may often fail on the application of the test of several genera and of many 

 species. 



Front entirely corneous, anterior margin free, not articulating with a 

 coriaceous clypeus. 

 First joint of tarsi elongate or moderate, never very short, tarsi not 

 compressed; gense not sulcate. 

 Eyes less prominent than the sides of front, more or less transverse, 

 always emarginatc in front. 

 Anterior tibiae alone or none dilated. 

 Penultimate joint of tarsi entire. 



Anterior coxa; rounded; middle coxse always with dis- 

 tinct trochautin; antenna; never perfoliate, third 

 joint usually larger than the following. 

 Hind coxa? transverse, never oblique. 

 Front feebly dilated at the sides. 



