SYRPHIDAK OF MAINE. 24! 



irregularly outlined, extending practically the full length and varying 

 in width. 'At the approach to metamorphosis these adipose , masses in- 

 crease in extent sometimes covering nearly the entire dorsum except 

 the blood-vessel. At times also the body fluid invades more or less the 

 fatty bodies appearing as outlying pulsating pockets. 



Puparium (Fig. 33-14, 15). Length 8 to 8.25 mm., width 3.5 to 4.3 mm., 

 height 3.75 to 4 mm. Testaceous brown, naked, smooth except for 

 slight remains of the transverse wrinkling of the larva. Broadest in 

 front of the middle, nicely rounded in- front, descending rapidly at 

 the -posterior end to the projecting respiratory process. 



Adult (Fig. 33-9, 16} . Length <3, $, 10 to 12.5 mm. Description, 

 slightly modified after Osten Sacken (39, p. 139). 



Female (Fig. 33-9) : Face and cheeks yellow, a faint grayish spot 

 on the cheeks under the eyes. Front and vertex shining black with 

 black pile; the front on both sides along the eyes with a broad border 

 of yellowish pollen sometimes meeting the similar border of the oppo- 

 site side. This pollen continues in dilute form down the sides of the 

 face crossing narrowly beneath the antennae. Eyes pubescent (in many 

 specimens the pubescence is very much rubbed off and very difficult to 

 perceive). Antennae inserted beneath a double arched ledge of front. 

 The dark color of the front begins immediately above their root 

 forming a blackish brown arch with a projecting angle in the middle. 

 Antennae dark brown; third antennal joint below and the bare arista 

 sometimes more or less reddish. Face in 'profile perpendicular beneath 

 the antennae produced but little below the eyes, slightly concave 

 beneath the antennae to oblique tubercle, receding below (Fig. 33-76). 

 Thorax dull greenish with but little luster; in well preserved speci- 

 mens with three faint dorsal longitudinal darker stripes, divergent 

 posteriorly; scutellum dull yellowish with a slight bluish reflection. 

 The black pile of scutellum and dorsum of thorax changes to yellow 

 on the sides of the latter where it is also much thicker and longer. 

 Third longitudinal vein nearly straight; anterior cross-vein a third of 

 the way from base to apex of the discal cell; anterior outer angle of 

 first posterior cell acute. Entire sub-costal cell brown; root of wings 

 as far as humeral cross-vein and the costal cell slightly tinged with 

 brown. Legs slender; coxae and basal third of femora black; on the 

 hind pair the black reaches beyond the middle of the femora ; hind 

 tibiae often with a brownish ring; four anterior tarsi brown the root 

 of the first joint often reddish ; hind tarsi dark brown. 



Abdomen oval slightly broader than thorax ; about twice as long ; 

 with three prominent yellow cross-bands, the first interrupted in the 

 middle, all attaining the lateral margins. First segment entirely black; 

 second segment with a yellow elliptical spot about the middle on each 

 side prolonged usually as a narrow neck which reaches forward and 

 touches the margin. Third and fourth segments each with a yellow 

 cross-band on its anterior half, the hind margins of these bands very 

 gently biconvex with a very shallow sinus at the middle; on each side 



