SYSTEMATIC ACCOUNT. 55 
present; mesopleure bare; auxiliary vein rudimentary; costa reaches fourth vein, but is 
very weak beyond the third; discal and second basal cells confluent; anal cell and anal 
vein present. 
The genus was based on the European G. distigma Meigen. G. pruinosus 
Bigot, from Tunis, is the only other Palearctic species. The genus Gitonides, 
which does not seem to me to be distinct, includes only the species G. 
perspicax Knab, from Hawaii, the Philippines, and India. The data suggest 
that it may have been introduced into Hawaii. ‘These three are the only 
species of the group now known. 
G. distigma breeds in the flower-heads of composites, and the larve are 
suspected of being aphidophagous. G. perspicax has been bred from larve 
feeding on mealy-bugs (Pseudococcus). 
I have seen the types of G. perspicax, and have examined European 
material of G. distigma, identified by Bezzi and by Kertész. 
Pseudiastata Coquillett. 1908. Proc. Ent. Soc. Wash., 9, 148. 
Arista minutely pubescent; three orbitals, anterior one convergent, posterior one nearer 
to verticals than to middle orbital; front covered with small black hairs, as in Pseudo- 
phortica; vibrisse large; carina very small; eyes bare; two dorsocentrals; prescutellars 
present; preapicals on first tibize, several bristles near the apices of second and third tibie, 
as in Pseudophortica; auxiliary vein rudimentary, but continued as a shadow to costa; 
costa twice broken, with a large bristle just before the distal break and two such bristles 
just before the proximal one; costa reaches fourth vein; discal and second basal cells 
confluent. é 
There is a single species, P. nebulosa Coquillett. It bears considerable 
superficial resemblance to the genus Sapromyza, and it was first described 
as a geomyzine. Examination shows many points of resemblance to the 
genus Pseudophortica, from which it is easily distinguished by its arista. 
Only one specimen has been recorded, that was taken at Plummer’s Island, 
Maryland, by H.S. Barber. Mr. Barber tells me that it was taken at night, 
at a light. I have examined this specimen, and a second one that agrees 
with it in all essential points, taken at Alajuelo, Panama, by A. Busck. 
Idiomyia Grimshaw. 1901. Fauna Haw., 3, 50. 
This genus is unique in the possession of an extra cross-vein, between the third and 
fourth veins, near the posterior cross-vein. It is described as having the following char- 
acters: auxiliary vein rudimentary; anal cell present; discal and second basal cells con- 
fluent; eyes pubescent; arista plumose; three orbitals, disposed as usual; two pairs of 
dorsocentrals; two pairs of scutellars, posterior ones crossed; eyes oblique. Mr. Lamb 
writes me that the vibrissa is absent. 
Six species are described in ‘‘ Fauna Hawaiiensis,” all from the Hawaiian 
Islands. The type is I. perkinsi Grimshaw. The species occur on four of 
the larger islands of the group. 
Zygothrica Wiedemann. 1830. Achias Dipt. Genus, 16, 3. 
Drosophilura Hendel. 19138. Ent. Mitt., 2, 387. 
? Sphyrnoceps de Meijere. 1915. Tijds. Ent., 58, suppl.; 58. 
Arista plumose; two or three orbitals; vibrissee present; ocellars present; postverticals 
large; face protuberant; carina large; head broader than thorax; antenna inserted opposite 
middle of eye; proboscis longer than height of head; no prescutellars; preapicals evident on 
second and third tibie; discal and second basal cells confluent; costa twice broken, reaches 
apex of fourth vein. 
The type species is Achias dispar Wiedemann, described from Brazil and 
since recorded from Peru, Bolivia, and Panama. Z. aldrichii Sturtevant, 
from Panama, is the only other American species. Sphyrnoceps brunneus 
de Meijere, from the East Indies, probably also belongs here. I have 
discussed the synonymy of these forms elsewhere (Sturtevant, 1920, Proc. 
U.S. Nat. Mus. 58, 155). 
