Psoloessa delicatula (Scudder)

 
Adult male Adult female

Common name - Brown-spotted range grasshopper (Heifer, 1972).

Geographic distribution - from Manitoba (Canada) to Texas; west to British Columbia (Canada), Washington, Oregon and California (Otte,1981). In Colorado it is found throughout the state.

Colorado Distribution Map

Habitat - found in areas of short grass with many bare patches and in dense sagebrush (Anderson et al., 1979; Scoggan and Brusven, 1972).

Food habits - feeds on grasses and sedges. Some of its preferred foods are blue grama, sand dropseed, cheatgrass brome, threeawn, needlegrass, wheatgrass, needleandthread, sedges and fescue (Brooks, 1958; Hewitt, 1977; Kumar et al., 1976).

Eggs - eggs are tan and arranged in two columns, 18 per pod. Average egg length, 4.9 mm; average diameter, 1.3 mm (Onsager and Mulkern, 1963).

Nymph - five instars (Scoggan and Brusven, 1972).

Adult - small size. General color is dark gray to green. Face is nearly vertical. Vertex is rounded. Antennae are slender. Lateral carinae of pronotum are constricted in middle. Median carina is slightly notched in middle. Dorsal posterior margin of pronotum is an obtuse angle. Conspicuous black markings usually run behind eyes, on sides of pronotum and near lateral carinae. Tegmina are brownish-gray with a row of four to six rectangular black spots on the midline. Wings are clear. Hind femora have two or three black bands on upper surface; the middle band is triangular. Hind tibiae are red or yellowish. Male length, 12 mm; female 18 mm (Brooks, 1958; McNeill, 1896).
 
Pronotum (Top view) Tegmen Head (Front view)

Seasonal history - an early-season grasshopper that overwinters as a third-instar nymph. Adults are present from May to July and lay their eggs in early summer. They are not abundant during mid-summer, but their numbers increase as nymphs hatch in the autumn (Anderson et al.,1979; White and Rock, 1945).

Abundance and importance - common on the grassland but rarely becomes a pest (Brusven, 1967; Helter, 1972).

P. delicatula fact sheet from the Field Guide to Common Western Grasshoppers
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