THE BLACK FLY OF CITEUS. 41 
portion of the case is removed the ventral part appears under the microscope as dark 
Thrown and more or less irregularly mottled. Submarginal area with usually 20 spines 
form in g a ring, varying considerably in length, but caudal pair nearly always longest. 
Spines curved outward. A pair of hairs present on caudal margin caudad of vasiform 
orifice. Spines on dorsum small excepting two pairs on abdomen and three pairs 
on thorax. (Number and arrangement shown in PI. X, D.) Vasiform orifice 
prominent, being on a tubercle, but small and somewhat triangular in shape, tending 
to circular (PI. XI, E). Operculum almost entirely fills orifice, obscuring lingula 
except for a very small portion at tip. Cephalad of orifice a pair of minute setse is 
situated, one set on each side. Margin of case dentate, teeth large and bluntly rounded 
(PI. XI, F). A space of 0.1 mm. is occupied by six or seven teeth. On this feature 
alone the case is easily separable from those of the other species. At base of teeth, 
forming a ring around the case, is a series of minute, clear, porelike areas. On the 
leaf the case is jet black with the dorsum somewhat arched and the abdominal 
segments marked, but not distinctly separated. On the margin all around is a nar- 
row cottony lateral wax fringe. This sometimes extends mesad, irregularly covering 
the submarginal area, but dorsal secretion is usually absent. 
ADULT FEMALE. 
Length from vertex to tip of ovipositor 1.12 mm.; color brown, under the micro- 
scope a deep wine color with darker shadings on head, thorax, and tip of abdomen. 
Vertex rounded and possessed of a slight median ridge. Eyes very dark brown. An- 
tenna? (Pi. XI, F) 0.311 mm. in length, segment III 0.117 mm. long, segment IV 0.018 
mm., segment V 0.033 mm., segment VI 0.041 mm., segment VII 0.0367 mm. Seg- 
ments III, V, and VII with a sensorium near the distal extremity of the segment 
(PI. XI, H). Labium yellowish, tipped with black. Legs yellowish, shaded on 
femora with dusky. Femora and tibia? of the hind legs considerably darker than 
the others; length of hind femora 0.288 mm.; hind tibia? 0.432 mm. Tarsi having 
proximal segment 0.1 mm. and the distal 0.06 mm. Proximal segment armed on 
its distal extremity with one large spine and several smaller ones; foot normal, with 
paronychium straight and hairy. Forewings 1.268 mm. long and 0.76 mm. wide at 
the widest part. Radial sector heavy, yellowish brown in color, and much curved. 
Cubitus very fine, long and' slightly curved, that portion of the wing below it form- 
ing a more or less distinct lobe. Wings (PL XI, I, J) a deep smoky color, except as 
follows: A line following the cubitus and a rather large spot near its distal extremity 
are colorless. A line following radial sector from its distal extremity to almost its 
median curve and another crossing it almost at right angles are colorless, giving the 
appearance of a white cross on a dark background. Marking in some wings not so 
evident, but there is one curved colorless line angling across the wing a short distance 
above and parallel with the radial sector. Border of this white line more heavily 
shaded than remainder of wing. Margin of wing armed with a series of rather promi- 
nent teeth directed toward the distal extremity of wing. Each one of these armed 
with one prominent spine and usually three smaller ones (PI. XI, I, J). The margin 
formed by these teeth and a line along their bases is bright wine red. Hind wing 
uniformly smoky 7 , with the vein yellowish brown. 
ADULT MALE. 
Much smaller than female, measuring only about 0.79 mm. from vertex to tip of 
claspers. Antenna? 0.261 mm. in length, segment III 0.117 mm., segment IV 0.015 
mm., segment V 0.026 mm., segment VI 0.031 mm., segment VII 0.023 mm. Seg- 
ment III having two small sensoria near its distal extremity (PL XI, G), segments 
V and VII having only one. Color yellowish or reddish brown. Hind femora 0.24 
mm. and hind tibia 0.4 mm. in length. Marked as in female. Claspers 0.126 mm. 
long. Near their distal ends there are a number of jagged teeth and they are armed 
