244 S. W. Williston — Nexo Diptera. 



than fifth. Long, corp. 9'"'" ; long, al, 9'""', Olympia, Wasliington 

 Territory, — H. K, Morrison, 



The present species is a most interesting addition to our fauna. 

 Hitherto only one, possibly two, species of this family and belonging 

 to the short-proboscid division, have been described from North 

 America. The family is subtropical, and the occurrence of the pres- 

 ent, the first North American representative of the rhynchocephalous 

 division (JVeinistrinini), from such high latitude is remarkable, and, 

 moreover, is a striking example of the resemblance pointed out by 

 Baron Osten-Sacken between the Western Asiatic and our Pacific 

 faunoe. Of the genus Rhynchocejyhalus, Schiner considered R. Tau- 

 scheril, from the region south of the Black Sea, as tlie type, and 

 which, evidently, is the only known species, beside the present, that 

 will ultimately remain in the genus, so diverse are the other two 

 species, from the same regions, hitherto placed with it. To H. Tau- 

 scherii (Meig. Sys, Besch,, vol, vi, pi, 66, fig. 6) the present species 

 shows a very close resemblance, the length of proboscis and color of 

 the head being the chief differences. 



Of the Nernistrmini, a fossil species has been described by Dr. Scud- 

 der from the Tertiary shales of Florissant, forming the type of a new 

 genus [Palemholus, Bui. U. S. Geol. Sur,, vol. iv, No. 2, p. 526). So 

 far as I can judge, the genus is nearly related to RJiynchoeephalus. 

 I would differ somewhat from Dr. Scudder's excellent interpretation 

 of thiSj the most intricate neuration among diptera. It is not the 

 anterior, but the posterior, intercalary vein that is present, as in 

 many Midasidm. The vein which he describes as the anterior inter- 

 calary, is composed of the anterior basal transverse and the fifth 

 longitudinal. Dr. Loew defined the family as having both interca- 

 lary veins, but I can find no evidence of the anterior one. 



Silvius pollinosus, n. sp. s . 



Small, black, thickly grayish white pollinose. Head black, shin- 

 ing, concealed beneath dense gray pollen, ocelli very distinct, area 

 not denuded. Frontal callosity black, shining, doubly rounded 

 above, doubly concave and pointed below. Face with three shining 

 black spots, the middle one smaller, sometimes obsolete. Antennae 

 fuscous, second joint less than half as long as first, basal joint gray- 

 ish pollinose and black pilose, base of all the joints somewhat luteous, 

 the third especially so on the inner and upper sides, quinque-annu- 

 late, terminal portion black. Palpi reddisli, proboscis black. Tho- 



