Key to males and females of the Delia pruinosa species group

1 Males: Eyes narrowly separated above antennae. Sternite V incised at hind margin.................................. 2

– Females: Eyes widely separated above antennae. Sternite V not incised at hind margin............................. 5

2 Hind tibia with apical av-seta short and notably robust (Fig. 7, arrow). Surstyli (Fig. 10) very broad in posterior aspect. Sternite IV wider than sternite V; lateral margins of sternites III and IV with long, lateroclinate setae (Figs. 8, 9) D. pruinosa

– Hind tibia with apical av-seta longer, unremarkable (Fig. 6, arrow). Surstyli slightly (Fig. 19) to decidedly narrower (Figs. 27, 37) in posterior aspect. Sternite IV not exceeding width of sternite V; sternal setae shorter, suberect, best developed on anterior third of sternite III (Figs. 17, 18, 26, 35, 36)............................................................... 3