2 MEMOIRS ON THE COLEOPTERA. 



North America, this continent being comparable with entire Eurasia 

 in its evolutionizing influence so to speak. On looking over my 

 previous paper, devoted wholly to a part of the large tribe Myr- 

 medoniini, it can be observed readily how little the faunas of the 

 two coasts have to do with one another. Taking only large genera 

 or subgenera for example, it will be seen that such groups as Ste- 

 thusa, Micrearota, Hilara, Noverota and Pancota (Dolosota), each 

 comprising numerous species, are confined to the Atlantic regions, 

 not crossing the Rocky Mountain system, while the similarly 

 large groups Homalottisa, Anepsiota, Nemota, Microdota as there 

 considered, Adota, Tarphiota and Dimetrota, are confined to the 

 west coast regions, the last however not quite entirely, though the 

 eastern forms are subgenerically different from the more normal 

 west coast Dimetrota, and the first extends eastward to the great 

 lakes. This latter distribution is, however, very frequent in the 

 case of west coast genera, many of them extending eastward nearly 

 or perhaps entirely across the continent in far northern latitudes, 

 but having very little tendency to spread eastwardly in the more 

 southern regions; w r ell known instances are Buprestis of the langi 

 type, Phellopsis and many others in nearly all the large families. 

 The average collector having before him a large assortment of 

 Aleocharinids, generally regards the task of arranging them, even 

 generically, as well-nigh hopeless, and in fact it is rather hopeless 

 unless a great deal of close and careful study be bestowed upon 

 them. Experience under these conditions will gradually render 

 the subject clearer. The procedure that I would recommend is 

 as follows: First mount the specimens, which in the moist and 

 pliable state have been cleaned and straightened, neatly on card 

 points so that the plane of the upper surface shall be horizontal, 

 by the hind part of the metasternum and base of the abdomen, 

 using very little of some strong and quickly setting soluble cement. 

 On inverting the specimen so mounted under an objective of low 

 power -a hand lens is useless as a rule for work in this subfamily 

 except for superficial comparisons, the legs may be bent aside by 

 means of a fine needle or pin-point so as to expose the mesosternal 

 region. Having the specimens in correct form for study, the 

 first point to observe is the number of joints composing the tarsi, 

 and this is the most difficult of all, the peculiar arrangement of 



