Description of larvae of M. coelamboides (Fall, 1923)

(Figs 17–21)

Source of material. The larvae studied were collected ex societate imaginis (Fig. 16) at the following locality: USA: California. Inyo Co.: Death Valley National Park, Salt Creek, ca 20 km west of Furnace Creek, off CA Route 190, 11.iv.1999, 36°35.436′N 116°59.433′W, four instar III, Y. Alarie leg. The identification is safe as M. coelamboides was the only Deronectina species collected at that location .

Diagnosis: Instar III larva of M. coelamboides can readily be distinguished from that of M. panaminti by its larger size, HL = 0.99–1.05 mm, HW = 0.77–0.85 mm, U1 = 2.20–2.35 mm (Table 1), higher number of secondary setae along anteroventral margin of metafemur (> 13) and metafemur as a whole (> 43) (Table 2), and broader abdomen (Fig. 17).

Body (Fig. 17): Measurements and ratios that characterize the body shape are shown in Table 2.

Head (Fig. 18): HL = 0.99–1.05 mm, HW = 0.77–0.85 mm, FRL = 0.74–0.83 mm, OCW = 0.52–0.61 mm; ventroapical margin of frontoclypeus with 32–33 spatulate setae [= lamellae clypeales of Bertrand (1972)].

Thorax (Figs 17, 20–21): L3 = 2.78–2.88 mm.

Abdomen (Figs, 17, 19): LAS (Fig. 19) = 0.36–0.39 mm. Urogomphus. U1 = 2.20–2.35 mm, U1+ U2 = 2.71–2.84 mm, U1/U2 = 4.19–5.59.

Chaetotaxy: Lateroventral margin of PA with 7–8 secondary spine-like setae (Fig. 18); secondary leg setation detailed in Table 2 and Figs 20–21.

Ecology: Salt Creek is part of Death Valley National Park. It is a significant water feature in the park, though it is often only a seasonal creek. Adult and larval specimens of M. coelamboides (Figs 16–17) were collected along the creek margin.

Distribution: So far only known from a few scattered records in southeastern California and New Mexico, USA. (Zimmerman & Smith 1975).