1985] 
Burger — Stonemyia and Pegasomia 
121 
shape of the body of calif ornicus is similar to the bee-like appear- 
ance of the Stonemyia species, the abdomen being stouter and more 
rounded, compared to Pilimas abaureus and ruficornis, whose 
abdomens are more slender and more nearly parallel-sided. 
I therefore believe that californicus was mistakenly placed in the 
genus Pilimas and belongs instead in Stonemyia. Since Brennan 
designated californicus as the generotype of Pilimas, a new name is 
needed in which to place abaureus and ruficornis. Pegasomyia, new 
genus, is hereby proposed and contains these two species. The name 
is taken from Pegasus, the legendary flying horse of Greek mythol- 
ogy. Pilimas becomes a synonym of Stonemyia, new synonymy. I 
designate Corizoneura ruficornis Bigot, 1892 as the generotype of 
Pegasomyia. 
Stonemyia can be unequivocally separated from Pegasomyia by 
the presence of a row of bristles on the ventral surface of the scutel- 
lum and the relatively unexpanded subscutellum. Pegasomyia con- 
tains two western species, P. abaurea (Philip) and P. ruficornis 
(Bigot). Stonemyia in North America contains three eastern taxa: 
isabellina (Wiedemann), rasa (Loew) and tranquilla tranquilla 
(Osten Sacken), and three western taxa: calif ornica (Bigot), tran- 
quilla fera (Williston) and velutina (Bigot). 
Six Palaearctic species have been placed in Stonemyia: yezoense 
(Shiraki), enokizonoi (Ouchi), hispanica (Krober), caucasica 
(Krober), tigris (Bigot) and bazini (Surcouf) ( =chekiangensis 
(Ouchi)) (Moucha, 1976; Leclercq and Olsufjev, 1975). Stonemyia 
yezoense is a well-known Japanese species and has bristles beneath 
the scutellum as do the North American species. St. caucasica has 
well-developed ocelli and could be a Stonemyia species but this 
needs to be confirmed. The type male of St. enokizonoi, collected 
from Yaku Island off the southern coast of Japan, is thought to 
have been destroyed in Shanghai, China during World War II 
(Hayakawa, personal communication). It is very close to St. 
yezoense and may be conspecific with it. Study of hispanica by 
Schacht and Portillo (1982) revealed that it is a species of Phi/oliche 
( Ommatiosteres ), not Stonemyia. Chainey (1983) provided a com- 
plete description and discussion of P. hispanica. It seems unlikely 
that tigris should be placed in Stonemyia since Bigot mentions in his 
original description that ocelli are absent, whereas they are well- 
developed in all known Stonemyia species. It is possible that tigris 
