OF WASHINGTON. 171 



tinental Alaska, although but little explored, does not appear to 

 possess any species peculiar to itself and is plainly only a westward 

 extension of the boreal fauna of North America and in no way 

 different from the fauna of the Rocky Mountain system or 

 that of the Lake Superior region. 



This paper was discussed by Dr. Gill, who stated that the distri 

 bution mentioned by Mr. Schwarz is somewhat reinforced by 

 the distribution of other animals, and that it was also somewhat 

 variant. Mollusks and fishes of Alaska are European and 

 Siberian, and same may be said of certain of the mammals. Mr. 

 Schwarz added that the Alaskan fauna constitutes a well-marked 

 faunal region of the country, comprising one peculiar family, the 

 yiEgialitidaa, and a host of genera and species which do not occur 

 elsewhere. 



Mr. Schwarz also read some remarks on the West Indian 

 sugar-cane borer ( Xyleborus perforans Woll.) and dwelt upon- 

 the difficulties in ascertaining whether or not this species really 

 occurs in the United States. The females of quite a number of 

 species of Xyleborus are utterly indistinguishable, for the present 

 at least, and reliable determination can only be made from the 

 males, which are very rare and difficult to obtain. He had never 

 seen in North American collections a male which exactly 

 corresponded with that of X. perforans, and the description of 

 X. retusicollis Zimm. leaves some doubt regarding its identity. 

 Eichoff 's X. affinis is said to be identical with X. perforans, but it 

 is doubtful whether the type of the male of A. affinis came 

 from the West Indies or the United States. As a peculiarity 

 in the history of X. perforans, Mr. Schwarz pointed out the 

 sudden and simultaneous appearance of the species in the sugar 

 plantations throughout the West Indies. The cultivation of 

 sugar-cane in the West Indies is very old, but until quite recently 

 nothing was heard of the attack of the beetle on sugar-cane in 

 any of the islands. 



This communication was briefly discussed by Messrs. Riley 

 and Howard. Dr. Riley said that the sudden appearance of the 

 sugar-cane borer was probably due to the general introduction of 

 the ribbon-cane from Ceylon or some other East Indian point. 



Under the head of short notes and exhibition of specimens, 



