192 PROCEEDINGS ENTOMOLOGICAL SOCIETY 



ft 



Two male specimens reared from Nacaleia indicata Fabr., 

 at Rio Piedras, Porto Rico, January 24, 1912, by T. H. Jones. 



From the foregoing it seems evident that the reference of 

 Sturmia sc : tizurce Coq. to the genus Argyrophylax by Doctor 

 Townsend 1 is obviously erroneous. 



In the sense of Coquillett this form is a true Frontina as the facial 

 ridges beara strong row of bristles quite to or beyond their middle. 



Because of the remarkable superficial resemblance between 

 A. albincisa Wied. and Pseudochceta argentifrons Coq. I have 

 included drawings of the latter species also. 



In discussing Mr. Walton's paper, Dr. Townsend stated that 

 he believed the determination of Argyrophylax albincisa to be 

 correct; and emphasized the importance of securing positive 

 identifications of Brauer & Bergenstamm's American genotypes. 

 He pointed out that, while these authors went as far as anyone 

 could feel justified in going on external adult characters alone, 

 they did not possess, as \\e do today, the reproductive characters 

 to demonstrate to them the value of certain slight but constant 

 external adult characters for separating distinct forms, and 

 hence did not include such slight characters in their system; as a 

 result, their generic characterizations will often apply equally 

 well to very distinct forms. The European species which stand 

 as genotypes of their genera are quite well known ; but the Ameri- 

 can forms are by no meany well kno^n, and every positive de- 

 termination of their American genotypes represents a distinct 

 gain. 



Under the head "Short Notes and Exhibition of Specimens" 

 the following were presented: 



A NEW BEE OF THE GENUS DIANTHIDIUM. 



BY S. A. ROHWER, Specialist in Forest Hymenoptera, Bureau of Entomology. 



Dianthidium arizonicum, new species. 



This species is extremely closely allied to texanum Cresson but the 

 seventh sternite is broadly black and the front between the antennae has 

 two rounded ridges. The next differs from that of texanum in that the 

 cocoon does not extend beyond the surface of the next. 







1 Taxonomy of the Muscoidean Flies, p. 98. 



