6 BULLETIN 432, U. S. DEPARTMENT OF AGEICULTTJEE. 



thorn-like point on upper side; arista black, distinctly thickened at base and 

 tapering to near its middle, pubescence indistinguishable, length of arista short 

 of twice the length of antennae; face yellow, slightly concave, central keel 

 rounded ; cheeks yellow, higher posteriorly than anteriorly, and at highest point 

 about one-half as high as eye, marginal bristles distinct ; vibrissa strong, dif- 

 ferentiated from marginal bristles ; proboscis and palpi yellow ; occiput unpro- 

 jecting on upper half. Mesonotum with disk entirely glossy black, with some- 

 times an indication of grayish pollen, or with the central portion in front of 

 scutellum yellow, more rarely with two narrow black stripes on sides, and the 

 central yellow portion carried forward at its anterior margin, slightly beyond 

 middle, as narrow lines which more or less distinctly intersect the broad discal 

 black mark, giving the disk the appearance of having five stripes, or a pattern 

 somewhat similar to that of Agromyza melampyga; lateral margins of mesono- 

 tum broadly yellow ; humeri with a black spot ; four pairs of dorso-central 

 bristles on mesonotum ; no setulse on disk ; pleurae yellow with black variega- 

 tions; squamge yellow, the fringe brownish or grayish; scutellum all black or 

 with the disk yellow, two scutellar bristles present. Abdomen from almost 

 entirely yellow to almost entirely black, posterior margins of segments narrowly 

 yellow. Legs slender, yellow, sometimes with fore tibiae and tarsi blackened, 

 all tarsi brownish. Wings as figure. 



Length 2-2.5 mm. 



The stages of this species are as follows : ^ 



THE EGG. 



(PI. I, fig. 2, a.) 



Egg elongate kidney-shaped, rounded at each end. Color opaque white, with- 

 out distinct punctation, markings, or ornamentation of any kind. Two or three 

 days after deposition the embryo, as seen through the chorion, shows 14 

 segments. 



Length 0.40 mm ; diameter 0.18 mm. 



THE LARVA. 



(PI. I, flg. 3, and PI. II, figs. 1 and 2.) 



Length 4 mm ; greatest diameter 0.75 mm. Slender, nearly cylindrical, 

 slightly thicker near cephalic end, which is obtusely pointed. Mouth-hooks 

 black and exposed to view when at rest. Body segments plainly defined, armed 

 at either end near sutures with slender areas of microscopic spinous processes. 

 Anal extremity abruptly truncate and bearing the spiracular appendages close 

 to the dorsal line. Anterior stigmatal projections plainly visible and formed 

 as in figui'e 3, a. Color of body in life dirty white, the surface of the skia 

 having a distinct gloss, as shown in figures 7 and 8 ; after death and preserved 

 in alcohol, opaque, nearly white. 



THE PUPA. 

 (PI. I, flg. 4.) 



Pupa somewhat elongate, flattened dorso-ventrally. White when freshlj^ 

 formed, turning yellow and growing darker as pupa advances in development. 

 Cephalic end obtusely conical ; posterior end more rounded. Segrnents strongly 

 constricted at sutures. Stigmatal processes, both anterior and posterior, dis- 

 tinctly projecting. Length 2.5 to 3 mm. ; lateral diameter about 1 mm. ; dorso- 

 ventral diameter 0.60 mm. to 0.70 mm. 



1 The descriptions were written by W. R. Walton. 



