Noctuidae - Psaphidinae - Grotellini




Grotellaforma lactea (Stretch)1885

Cisthene lactea Stretch, 1885, Ent. Americana, 1: 103.

Grotella calora Barnes, 1907, Can. Ent., 39: 68.

Diagnosis: Grotellaforma lactea is a small, nearly pure white, species of the southwestern United States and Baja California del Norte. The forewing is white with the maculation reduced to a few black dots representing the antemedial and postmedial lines. In some individuals even these black dots may be completely absent. The hindwing is white but most individuals are suffused with dull gray. Wing length: mean = 8.75 mm, standard deviation = 0.49 mm, n = 10.

Distribution: Grotellaforma lactea is a desert species found in southern and western Arizona, and southeastern California in Inyo, San Bernardino, and Riverside. The species has also been collected in Baja California del Norte. The strength or presence of small black dots on the forewing is variable among individuals. No geographical variation is visible.

Adults have been collected in March and April in Arizona. The species is apparently two brooded in southern California with a spring brood and a second brood flying from July to September.

Identification Quality: Excellent

Larva: Unknown

Foodplants: Unknown

Grotellaforma lactea

This species could easily be confused with some species of Grotella, in particular Grotella stretchii, sampita, or septempunctata. The absence of tibial spines and the near absence of a frontal process will immediately separate lactea from any species of the genus Grotella. Grotellaforma lactea could also be confused with Homolagoa grotelliformis (a genus in the Eustrotiinae), but grotelliformis is a larger species; average wing length from base to apex is 8.75 mm in lactea, but approximately 11 mm in grotelliformis. Both species have black dots representing the forewing antemedial and postmedial lines. The dots are very small, few, and sometimes absent in lactea. In contrast the black dots are much more conspicuous in grotelliformis, three dots representing the antemedial line and four or five dots the postmedial line. A black dot is always present on the costa near the base of the wing in grotelliformis, but no such dot exists in lactea. A degenerate central protuberance is present in both species, but the protuberance is located near the clypeal margin in lactea, but close to the line connecting the antennal bases in grotelliformis.

Similar Species

Grotella stretchii

Grotella sampita

Grotella septempunctata