494 PROCEEDINGS OF THE ACADEMY OF [Sept., 
a very conspicuous curved hook; eighth sternite with two strong 
decurved bristles on the caudal margin. 
MaZe;— Length, 16 mm.; wing, 17.2 mm. 
Frontal prolongation of the head rather elongate, shining, dull 
yellow; palpi dull yellow, the two terminal segments brown. An- 
tenna short, the three basal segments yellow, remainder of the organ 
A\dth the basal swelling of each segment brownish black, the remainder 
yellow, the two terminal segments a little darker. Head brownish 
yellow, an indistinct brown median line extending the length of the 
head. 
Thoracic dorsum dull light yellow, unstriped or nearly so, the 
usual interspaces on the praescutum being a little more grayish 
only. Pleura yellow, sparsely whitish poUinose. Halteres rather 
long, slender, pale, the knobs darker. Legs with the coxae and tro- 
chanters dull yellow, the remainder broken. Wings grayish yellow, 
the costal region and the stigma brighter yellow; an interrupted 
vitreous band before the stigma, broadest in cell 1st Ri before the 
stigma and in cell 1st Mo, narrowly connecting the two along the 
cord; a small, indistinct, vitreous spot beyond the stigma. Venation 
as in Plate XVI, fig. 15. 
Abdomen dull brownish yellow. Male genitalia (see Plate XVIII, 
fig. 36) with the eighth tergite prominent, its caudal margin straight 
across. Ninth tergite (see Plate XIX, fig. 53) very long, subquad- 
rate, the caudal margin with a deep acute notch, the lateral lobes 
produced into long, somewhat curved horns which are directed 
slightly inward, the extreme tip ventrad. Ninth pleurite (see Plate 
XX, fig. 64) complete, rather small, the dorsal end sharply angular 
and barely attaining the ninth tergite; appendages two: a short, 
caudal-lying fleshy lobe with abundant long hairs (a), underneath 
the lobe is a large, powerful, chitinized hook directed dorsad and the 
tip outward, decussate with its mate of the opposite side; a flattened 
appendage lying more cephalad, its anterior face chitinized and 
notched; in a position of rest, the appendage lies beneath the extensive 
ninth tergite. Ninth sternite extensive, deeply notched beneath, 
bearing a fleshy, elongate-oval lobe which hangs subpendulously in 
the notch, but is attached to the sternite by one broad face. Eighth 
sternite (see Plate XVII, fig. 27) with the caudal margin broadly 
concave, at each end of this notch a single very large bristle, decussate 
with its mate of the opposite side. Penis-guard and the gonapophyses 
rather small, directed caudad, viewed from beneath (see Plate XXI, 
fig. 80) shaped somewhat like a trident. 
