194 
PACIFIC SCIENCE, Vol. XII, July, 1958 
Plecia cana Hardy 
Plecia cana Hardy, 1950, Hawaii. Ent. Soc. 
Proc. 14: 76, fig. 2a, b. 
A small dark-colored species related to P. 
tristis van der Wulp and differentiated by hav- 
ing the thorax entirely light gray with no 
black longitudinal stripes. The antennae are 
also distinctly 9-segmented; Edwards (1932, 
Treubia 14: 140) reported that the flagellum 
of tristis contains but four distinct segments. 
The male genitalia are distinctive from all 
known species of Plecia ; the broad flat- topped 
development of the median margin of the 
ninth sternum and the well-developed lobes 
on the posterior lateral margins will separate 
it; see figures referred to above. 
Length: Body, 4. 2-4. 5 mm.; wings, 5.4- 
5.8 mm. 
Known only from Benguet, Philippine 
Islands. 
Type in the U. S. National Museum. 
Plecia decora Hardy 
Fig. 5 
Plecia decora Hardy, 1950, Hawaii. Ent. Soc. 
Proc. 14: 78, fig. 3a-c. 
Fig. 5. Plecia decora Hardy. Genitalia, ventral view. 
I have studied a large series of specimens 
from the Rijksmuseum v. Natuurlijke Histo- 
ric, Leiden, and the Bernice P. Bishop Mu- 
seum New Guinea Exped.: Moss Forest 
Camps 13, 14, 16, 19, and 31, 2800 m.; from 
Scree Valley Camp, 3800 m., Nov. 1938 (L. J. 
Toxopeus) ; from Araboebivak, Wisselmeren, 
Paniai, New Guinea, 1750 m., Sept.-Nov. 
1939 (H. Boschma) ; and Daulo Pass, 2400 m., 
(Asaro-Chimbu div.), June 15, 1955 (J. L. 
Gressitt). 
Plecia dimidiata Macquart 
Related to P. forcipata Osten Sacken and 
forficula Edwards because of the forcipate de- 
velopment of the male genitalia. It is charac- 
terized from other Plecia by the coloration and 
by the details of the male genitalia. 
Predominantly dull reddish species, with 
three brownish-red vittae on the mesonotum. 
Coxae, trochanters, and bases of femora yel- 
lowish. Wings faintly brown fumose. Vein 
R 2+ 3 forms about a 40° angle to R 4+5 . Male 
genitalia as in Figure 5 and as described and 
figured in original. Gaspers bilobed as seen 
from lateral view, with a sharp pointed second- 
ary subbasal lobe arising from dorsal portion. 
Length: Body, 5. 0-7.0 mm.; wings, 8.0- 
10.0 mm. 
type locality: Mt. Tafa, Papua. 
Type in the British Museum (Natural 
History). 
Fig. 6a, b 
Plecia dimidiata Macquart, 1846, Dipt. Exot., 
Sup., p. 20, fig. 8. 
Related to P. borneensis Edwards but dis- 
tinguished by the genital characters. The ninth 
sternum has a well-developed flat-topped lobe 
in middle of hind margin and a pair of smaller 
submedian lobes. The claspers are expanded 
and dentate apically and extend well beyond 
apices of the tergum (Fig. 6d). The ninth 
tergum has a deep V-shaped cleft on hind 
margin (Fig. 6b). 
The mesonotum is chiefly semipolished 
rufous with the front margin broadly black- 
ened. The black coloration extends to a level 
slightly behind the humeri. The pleura are all 
black. The legs are all black with black pile. 
The femora are moderately swollen. The 
