352 BULLETIN UNITED STATES GEOLOGICAL SURVEY. 



common in all parts of California; I also have specimens from Utah, 

 Colorado, and Northern New Mexico. To my knowledge, it has never 

 been found east of the Mississippi. The suggestion that 8. pyrastri may 

 have been accidentally introduced in California, and is gradually spread- 

 ing eastward, may be met by the fact that Say's Syrphus affinis, which 

 is nothing else but S. pyrastri, was caught by that entomologist near the 

 Arkansas Eiver as early as 1820, and does not seem to have advanced 

 eastward since. The occurrence of this species in the west gains a 

 peculiar significance from its simultaneous occurrence in Chili, recorded 

 by Macquart. 



Not all the coincidences with the European fauna just alluded to be- 

 long to the whole western fauna. Many are peculiar to California only, 

 although, owing to our imperfect knowledge of the western Biptera, we 

 are often unable to state which among them belong to the one or to the 

 other category. 



The affinities with the Chilian fauna seem to be especially Californian. 

 Besides the case of Syrphus pyrastri, just mentioned, the following in- 

 stances have occurred to me : — The Tipulid Protoplasta vipio, from Cali- 

 fornia, belongs to a remarkable group, hitherto represented by three 

 species only: Macrochile spectrum, a fossil Dipteron from the Prussian 

 amber ; Protoplasta fitchii, from the Atlantic States ; and Tanyderus 

 pictus, from Chili. A somewhat analogous case is that of Eriocera cali- 

 fornica (Tipulidw), one of the Eriocerm, with enormously prolonged an- 

 tennae in the male. Of such Eriocerm I have hitherto known only three 

 species from the northern United States, two fossil species in amber, 

 and one from Chili (the Megistocera chilensis of Philippi, which I strongly 

 suspect to be an Eriocera). My new genus Bhaphiomidas (Midaidw) has 

 . its nearest relative in Mitrodetus from Chili. The genus Clavator (Asi- 

 lidce) from Chili, if my identification be correct, is represented in Cali- 

 fornia. The most interesting case is that of Apiocera, an anomalous 

 genus, intermediate between Asilidce and Midaidce, and hitherto found 

 only in Chili and Australia. I describe a species from California. 



Several genera of Biptera have not been yet found outside of the 

 limits of California, although it is very probable that they have a some- 

 what wider distribution. Such are Eulonchus (Cyrtidw), Bicolonus, 

 Ablautatus (Asilidw), Pantarbes, Paracosmus (Bombylidce), the extra- 

 ordinary genus Polymedon (Bolichopodidw), and Phyllolabis (Tipulidw). 



Ospriocerus (Asilidce), Lor dotus (Bombyl^^nd Eupeodes (Syrphidce) have 

 already been named as peculiar to the whole western region. 



Among the singularities of the Californian fauna of Biptera I will men- 

 tion the apparent rarity of Trichocera ( Tipul.), of which I found only a sin- 

 gle specimen of a rather peculiar species; the apparently frequent occur- 

 ence of Hygroceleuthus (Bolichop.), of which I found two species, before I 

 had collected more than one Bolichopus (in the Eastern States, a single 

 species of Hygroceleuthus is known, and some fifty species of Bolichopus) ; 

 the large number of Tipulce and the comparatively rare Pachyrrhinw ; 



