Apr. 2, 1917 
Wheat-Sheath Miner 
19 
Toward the end of the pupal period the pupa is visible through the 
puparium, showing the parts of the body distinctly, and movements in 
the legs can be seen three days before the emergence of the adult fly. 
ADULT 
A translation of Meigen’s description (2, p. 398) of the adult fly is as 
follows: 
Black; head, pleurae, and femora yellow; third antennal joint black, with distal 
thorn. Head light yellow, with black ocellar spot. Base of antennae yellow, third 
joint deep black, with black arista and apical spine. Notum and scutellum shining 
black, pleurae yellow, abdomen black and shining. Femora yellow, tibiae and tarsi 
piceous. Halteres white; wings grayish. 2/3 line. 
From an abundance of material of-both sexes the following description 
has been prepared: 
Cerodonta femoralis (Meigen). 
Adult male: Length, 2.0 to 2.5 mm.; wing expanse, 4.0 mm. 
Head as broad as the thorax; front broad, about one-third the width of the head, 
yellow except for a rectangular, black, ocellar spot at the vertex. Three pairs of 
frontal bristles present, reaching to the base of the antennae; one pair of ocellar bristles 
directed forward, situated at the two anterior comers of the ocellar spot; two pairs of 
vertical cephalic bristles, the outer pair divergent, the inner pair convergent; one 
pair divergent post vertical bristles present, located at the posterior margin of the 
ocellar spot. The three ocelli are located, one in the middle of the anterior margin, 
and the others in the middle of each of the lateral margins of the ocellar spot; ptilinum 
visible as a raised triangular portion, just above the base of the antennae. Oral vibrissae 
present, with four pairs of small hairs along the oral margin. Oral region, including 
the labella and genae, bright yellow. 
Antennae three-jointed, the first joint small, ringlike, and yellow; second joint 
larger, brown in color, with one medium-sized bristle, and a coronet of small bristles; 
third joint the largest, black oval, with a dorsal arista and an apical spur, pubescent. 
Occiput black; postorbital bristles present. 
Thorax for the most part shining black; pleural sclerites yellowish, or gray bordered 
with yellow. Four pairs of dorso central, one pair each of humeral, posthumeral, 
notopleural, supraalar, postalar, and scutellar apical bristles present. One propleural 
bristle, and one large and from two to four small mesopleural bristles present; stemo- 
pleurite with one bristle below the stemopleural suture, and a fanlike row of bristles 
above the middle coxa. 
Anterior coxae large, femora bowed; all coxae with bristles; femora with a small 
bristle on the posterior surface; anterior tibia alone without apical spine; coxae and 
femora yellow, tibia and tarsi brown. 
Wings grayish, basal portions of veins yellow, darker toward the tip; halteres whitish 
or yellow; squamae small, colorless. 
Abdomen viewed dorsally with six easily distinguished segments (the sixth is a 
genital segment) tapering posteriorly, uniformly hairy, black, except for a narrow 
yellowish line on the posterior margin of the first two and sometimes all of the seg¬ 
ments. The fifth segment is about twice as long as the preceding; the sixth is some¬ 
what globular in shape, with the posterior and ventral surfaces cleft, so that the two 
lateral plates form a pair of claspers. A chitinous process may protrude through the 
posterior cleft, and the penis hinges on this process, being directed forward. The 
dorsal surface of the penis near the hinge is open and the vas deferens, a flexible tube, 
follows along the chitinous process and enters the penis at the dorsal opening. The 
chitinous process upon which the penis is hinged appears to extend to the second 
