12 PROCEEDINGS OP THE NATIONAL MUSEUM akt. 5 



MUNDOPOIDES CISTHENARIA. new species 



Plate 1, fig. 5 



Tegmen about 11 mm. lono; (the extreme base lacking) ; black, 

 with tAvo broad colorless bands; the first, not far from base, about 1.5 

 mm. wide, suddenly and rectangularly constricted at inner lower 

 corner; the second, about 1.7 mm. wide, gently arcuate, placed 3 

 mm. beyond the first band, and 4 mm. from apex; apical margin 

 very narroAvly pallid. A round spot and a pale patch, with other 

 slight markings, are not natural, but due to abrasion. The second 

 band does not quite reach the costa at its upper outer corner, but on 

 the inner side appears to be prolonged along costa; costa hardly 

 arched; outer margin little curved, 5 mm. long; lower margin 

 straight (in absence of clavus), at least 9 mm. long. 



Tertiary of Kudia River, Siberia. 



Holotype.—C^it. No. 69613, U.S.N.M. 



The name of the species is derived from a superficial resemblance 

 to the moths of the Neotropical genus Cisthene; the central band is 

 placed nearly as in G. lunaris Walker. The shape of the tegmen re- 

 calls the Ricaniine genus Privesa^ but the structure is quite different. 

 There is a genuine resemblance to the American genus Bothriocera^ 

 species of which have a somewhat similar pattern of light and dark 

 markings. 



DIPTERA 

 Family BIBIONIDAE 



Genus PLECIA Wiedemann 



The genus Plecia is very widely distributed over the world, but 

 in any given fauna the species are few. It therefore seemed quite 

 scandalous for Handlirsch to describe 20 species from tertiary 

 rocks in two localities in British Columbia, there being only about 

 three to-day in the Avhole of the Nearctic region. However, I have 

 been able to distinguish four readily separable species in the Floris- 

 sant Miocene, and in now presenting 6 from a single Siberian lo- 

 cality I believe I err, if at all, on the side of moderation. I do not 

 yet believe that all of Handlirsch 's 20 species are distinct, but it 

 must apparently be recognized that in tertiary times Plecia was 

 very rich in species, as Tipula is to-day, and indeed was then. 



Brunetti, in his table of Indian Plecia^ divides the species into 

 two categories thus: {a) Third (3+4) longitudinal vein forking 

 some distance beyond anterior cross vein (nearly at half the length 

 of its lower branch), and always distinctly beyond the fork of 

 fourth vein, {h) Third longitudinal vein forking shortly beyond 

 anterior cross vein (distinctly before one- third of the length of its 



