Mar., 1913.] Life-Histories of Syrphidae V. 89 



pupal body becomes separated. The position of the seven pairs 

 of pro-legs and of the anal opening are shown as scars on the 

 ptiparium (Fig. 145, e, d). 



The color of the pupariuni with the pupa enclosed is a very 

 dark brown. When empty and dried it is brittle, and a very pale 

 ashy-brown in color. The larval wrinkling remains visible to a 

 slight extent. 



Pupae of this species were found in abundance at the sewage 

 disposal plant the middle of September. The walls of the vats 

 are of cement and are, much of the time, six or eight feet higher 

 than the level of the water. They are surmounted by an iron 

 railing. In the angles of this railing, or on the sides of the wall, 

 wherever a crevice or angularity presents itself, numbers of 

 puparia were found massed together and considerably over- 

 grown with webs of spiders. During the winter the empty puparia 

 in these locations form excellent nests for the spiders. 



Buckton, writing about E. tenax, states that the larvae buried 

 themselves in soft mud, each fonning a small dome over itself, 

 and so pupating under a shallow covering of mud. This method 

 of pupation would be a protection against drought. The pupa& 

 taken about the middle of September emerged as adults Septem- 

 ber 26, so that the duration in this stage was at least ten days to 

 two weeks. During the winter all the puparia that could be found 

 were empty or contained dead nymphs. Does the fly pass the 

 winter in some other stage, or can it be that the puparia left 

 exposed cannot winter and that nomially they bury themselves 

 in mud? If the latter is true, other pui^aria at this place may crawl 

 farther and bury in the soil. 



Adult. 



Description slightly modified after Williston, Synopsis N. A. 

 Syrph. pp. 161, 162.: 



"Male and female: Length S to 10.5 mm. Dark metallic 

 green, wholly shining. Thorax sometimes with a bluish reflection. 

 Eyes brownish, spotted with small round dots of darker (Plate 

 IV, Fig. 150). [This character sometimes disappears after death]. 

 The eyes are nearly bare, very slightly pilose near the top. Face 

 and front with grayish pile and pollen, a small spot on the tuber- 

 cle and the cheeks narrowly shining. Antennas brown, dorsal part 

 of third joint darker; often the first two joints yellowish; arista 

 bare. Thorax and abdomen with obscure yellowish pile. Dorsum 

 of the thorax in the female with five grayish -white stripes, the 

 middle one slender, linear, the two lateral ones broader (Plate 

 IV, Fig. 150). Scutellum with the same dark metallic green. 

 Tibise at the base, sometimes for nearly half their length, light 

 yellow; middle, sometimes all the metatarsi, yellowish; the femora, 

 except the tip, black; distal portion of tibiae blackish brown. 

 Wings hyaline." 



