Eritettix simplex (Thomas)

 
Adult male Adult female

Common name - Velvet-striped grasshopper (Helfer, 1972).

Recent synonymy - Eritettix variabilis Bruner.

Geographic distribution - Alberta and Saskatchewan (Canada), North Dakota and Wisconsin south to Mexico. Also from Rhode Island to Tennessee, Alabama and Georgia (Otte, 1981). Its Colorado range includes the eastern grasslands and the eastern mountain valleys (Hebard, 1929).

Colorado Distribution Map

Habitat - grassy hillsides and areas of dense vegetation (Anderson et al., 1979; Brooks, 1958).

Food habits - graminivorous, preferring blue grama, hairy grama, sunsedge, cheatgrass brome, side-oats grama, threeawn, needleandthread, sand dropseed, Sandberg bluegrass, Indian ricegrass and prairie sandreed grass (Brooks, 1958; Campbell et al., 1974; Kumar et al., 1976; Mulkern et al., 1969; Ueckert and Hansen, 1971).

Eggs - 12 to 20 pale yellow eggs are arranged in two columns within each pod. Average egg length, 4.4 mm; average diameter, 1.4 mm (Onsager and Mulkern, 1963).

Nymph - five instars (Ramsay, 1964).

Adult - small to medium size. Face is slanted back. Vertex is rounded. Antennae are clubbed at tip. Dorsal posterior margin of pronotum is rounded. Wings are clear. Lateral carinae are white and constricted near middle.
Male: general color is grey to greyish-brown. Two dark narrow lines are on head and pronotum. Tegmina are uniform, dark grey with pale streaks in the costal region and toward the apex. Lateral lobes of pronotum and thorax are darker than the rest of the body. Male length, 16 mm. Males fly noisily.
Female: long and robust. General color is grey with contrasting yellowish-white and dark markings, or bright green with yellowish white and dark lines. Tegmina are brown to green with a row of dark markings. Lower surfaces of hind femora are pale: outer surfaces are discolored longitudinally but not banded. Hind tibiae are buff with brown splotches. Female length, 16 to 24 mm (Brooks, 1958; Bruner, 1897).
 
Head (Side view) Pronotum (Top view)

Oviposition - occurs on both bare and vegetated sites (Onsager, 1963).

Seasonal history - an early season grasshopper that overwinters as a nymph. In the early spring it is found in the third or fourth instar. Adults are present from late May until late July. Eggs are produced early in the summer and hatch in late July (Anderson et al., 1979; Mulkern et al., 1964; Newton et al., 1954).

Abundance and importance - common and economically important on Colorado rangeland. It is abundant in early summer and fall but not during midsummer (Anderson et al., 1979; Gillette, 1904; Rottman, 1980).

E. simplex fact sheet from the Field Guide to Common Western Grasshoppers
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Biology of Common Colorado Grasshoppers
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