Machimus

Dennis, D. Steve & Barnes, Jeffrey K., 2013, Pupal cases of three Nearctic species of Machimus (Diptera: Asilidae), Zootaxa 3683 (5), pp. 561-570 : 569-570

Key to known pupal cases of Nearctic Machimus species

Dennis et al. (2008a) provided a key to the pupal cases of five species of Machimus ( M. lecythus , M. notatus , male M. occidentalis , M. paropus , and M. snowii ). This key is revised below to include M. latapex and M. prairiensis , and the female pupal cases of M. occidentalis and M. erythocnemius ( Hine, 1909) . The latter was not included in the original key because Scarbrough and Kuhar (1995) did not mention the presence or absence of a tubercle-like swelling (i.e., the palpal sheath) on the maxillary sheath. However, they did indicate that the maxillary sheath is entirely smooth and thus, it is assumed that there is not a tubercle-like swelling or palpal sheath.

1. Palpal sheaths sometimes visible on inner margin of maxillary sheaths towards apex of labral sheath; abdominal segment 8 with 0–4 (usually 1–4, on M. lecythus they are absent) dorsolateral bristlelike spines............................... 2

- Palpal sheaths not visible on inner margin of maxillary sheaths towards apex of labral sheath; abdominal segment 8 lacking dorsolateral bristlelike spines........................................................................... 4

2. Palpal sheaths present; anterior mesothoracic spines equal or subequal in length and posteriorly curved................ 3

- Palpal sheaths present or absent; outer or lateral anterior mesothoracic spine 1.5–2 times as long as inner anterior spine that is posteriorly curved......................................................... Machimus lecythus (Walker, 1849)

3. Abdominal segments 2–6 lacking short, dorsolateral spines, with 6 long spurs alternating with 7 short spines that are not bifurcate; segment 8 with 2 dorsal spurs and 1–2 dorsolateral bristlelike spines; male with 16 ventral bristlelike spines............................................................................... Machimus notatus (Wiedemann, 1828)

- Abdominal segments 2–6 with 1–2 dorsolateral spines on each side and 6 long spurs alternating with 5–7 short spines that may be bifurcate; abdominal segment 8 with 4–8 (usually 6–8) dorsal spurs, dorsolateral bristlelike spines usually absent; with 1–9 (male) or 4–8 (female) ventral bristlelike spines.................................. Machimus paropus (Walker, 1849)

4. Abdominal segment 8 with 1–3 dorsal spurs on each side of midline; long single spur or inner spur usually longer than outer spur(s)............................................................................................. 5

- Abdominal segment 8 with 2 dorsal spurs on each side of midline; spurs subequal in length.................................................................................................. Machimus prairiensis ( Tucker, 1907)

5. Proboscidal sheath with or without posterior medial groove or furrow anterior to 1–2 horizontal or vertical tubercles; abdominal segment 8 with 2 dorsal spurs on each side of midline..................................................... 6

- Proboscidal sheath lacking posterior medial groove or furrow anterior of single horizontal, terminal tubercle; abdominal segment 8 with 2–3 dorsal spurs on each side of midline........................... Machimus erythocnemius ( Hine, 1909)

6. Proboscidal sheath with posterior medial groove or furrow anterior of single horizontal or vertical tubercle; posterior antennal processes innermost process not widely separated from outermost processes; interior and sometimes outer, anterior mesothoracic spines usually curved posteriorly................................................................... 7

- Proboscidal sheath with or without medial groove or furrow anterior of two indistinct to minute vertical terminal tubercles; posterior antennal processes innermost process widely separated from outermost processes; anterior mesothoracic spines straight................................................................. Machimus occidentalis ( Hine, 1909)

7. Proboscidal sheath with horizontal terminal tubercle; abdominal segments 2–6 with row of 1–6 outer short dorsal spines on each side of alternating long spurs and short spines; segment 8 with 3–4 postspiracular bristlelike spines............................................................................................. Machimus snowii ( Hine, 1909)

- Proboscidal sheath with vertical posterior tubercle; abdominal segments 2–6 lacking row of short dorsal spines on each side of alternating long spurs and short spines; segment 8 with 5–6 postspiracular bristlelike spines.................................................................................................... Machimus latapex ( Martin, 1975)