210 
PACIFIC SCIENCE, Vol. XII, July, 1958 
Plecia morosa Edwards 
Fig. 20a, b 
Plecia tristis Edwards, 1927, Treubia 9: 362, 
fig. e, nec P. tristis van der Wulp, 1884, 
Notes Leyden Mus. 6: 251. 
Plecia morosa Edwards, 1932, Treubia 14: 140. 
A moderately small, opaque dark-brown to 
black species, readily recognized by the dis- 
tinctive genitalia of the male. The lack of de- 
velopment of the posterior lateral lobes of the 
ninth sternum (Fig. 20a) and the strong de- 
velopment of the lobes of the tergum (Fig. 
20 b) will separate it from related species. Ninth 
sternum about two times wider than long, the 
posterior lateral margins are rounded and the 
posterior median portion is raised into a semi- 
membranous mound. The claspers are capi- 
tate, rounded at apices, their bases seem to be 
fused with the margins of the sternum (Fig. 
20a). The ninth tergum is deeply cleft almost 
to its base on the hind margin; the lateral lobes 
are rather slender (Fig. 20 b) and extend nearly 
half the length of the segment beyond the 
claspers. 
Length: Edwards measured the body and 
wings as 6.0 mm. The specimens I have seen 
measured 3.35-3.75 mm. for the body and 
4. 5-5. 2 mm. for the wings. 
type locality: Tjibodas, W. Java. 
Type in the British Museum (Natural 
History). 
I have studied specimens from the type 
locality. 
Plecia ornaticornis Skuse 
Fig. 21 a, b 
Plecia ornaticornis Skuse, 1899, Linn. Soc. N. S. 
Wales, Proc. (2)3: 1374. 
A moderate sized species belonging in the 
complex which has the thorax entirely rufous. 
It appears most closely related to P. ruficornis 
Edwards but is larger and the male genitalia 
are differently developed. The lateral lobes of 
the ninth sternum are rounded rather than 
sharp pointed at their apices; the claspers are 
Fig. 20. Plecia morosa Edwards, a. Ninth tergum; 
b, ninth sternum. 
truncate, pointed on inner apices rather than 
rounded and a broad rounded median lobe is 
present on the hind margin of the sternum, 
also the lateral lobes are closer together as in 
Figure 21a. 
male: Eyes very sparsely pilose. Antennae 
chiefly black, 9-segmented, the second seg- 
ment slightly reddish on apical half. Legs 
black, segments slender. Wings light brown 
fumose, darker along costal margin. R 2 +3 
straight or nearly so, forming about a 75° 
angle with R 4+5 . Petiole of cell Mi one-half 
longer than r-m cross vein. Cubital cell 
slightly narrowed at apex. Genitalia charac- 
terized by strong lateral lobes of ninth sternum 
and small claspers shaped as in Figure 21a. 
Ninth tergum nearly divided into two plates 
(Fig. 21 b). 
