Efferia, Coquillett, 1893

Dennis, D. Steve, Barnes, Jeffrey K. & Knutson, Lloyd, 2008, Pupal cases of Nearctic robber flies (Diptera: Asilidae), Zootaxa 1868 (1), pp. 1-98 : 71

Key to known pupal cases of Nearctic species of Efferia

1 Labral sheath with low apical keel on posterior third or more; proboscial sheath with posterior tubercle.2

­ Labral sheath with raised, tubercle­like keel on posterior half; proboscial sheath with spine­like posterior process ............................................................................................................. Efferia benedicti (Bromley)

2 Proboscial sheath with single median tubercle on each side of midline; abdominal segment 8 with 2–3 dorsal posterolateral spurs on each side of midline and 5–8 bristle­like spines below and behind each spiracle...............................................................................................................................................................3

­ Proboscial sheath with 3–8 minute tubercles on each side of midline; abdominal segment 8 with 0­1 dorsal spurs on each side of midline and 2–3 bristle­like spines below and behind each spiracle...................4

3 Wing sheath rarely with median tubercle, abdominal segment 1 with 3 bristle­like spines behind each spiracle; abdominal segments 2–4 often with bifurcate dorsal spines; segment 8 with 2 dorsolateral spurs on each side and 6–14 subequal ventral bristle­like spines .................................. Efferia aestuans (Linnaeus)

­ Wing sheath with median tubercle; abdominal segment 1 with 6 bristle­like spines behind each spiracle; abdominal segments 2–4 without bifurcate dorsal spines; segment 8 with 3 dorsal spurs on each side and 16 long and short ventral bristle­like spines .................................................. Efferia triton (Osten Sacken)

4 Anterior mesothoracic spines apically rounded; wing sheath without median tubercle; abdominal segment 1 with 14 dorsal spurs; segment 8 with 14 ventral bristle­like spines .................... Efferia frewingi Wilcox

­ Anterior mesothoracic spines distinctly acuminate; wing sheath with median tubercle; abdominal segment 1 with 12 dorsal spurs; segment 8 with 2 ventral bristle­like spines ................. Efferia helenae (Bromley)