Noctuidae - Psaphdinae - Grotellini




Grotella tricolor Barnes 1904

Grotella tricolor Barnes, 1904, Can. Ent., 36: 240.

Diagnosis: The forewing ground color is white with a very slight cream-colored tinge to it. Grotella tricolor is immediately recognizable by the double forewing postmedial line filled by a broad light, dull orange band. It is not entirely clear if the postmedial line is truly double or whether the outer line should be interpreted as the subterminal line. The inner postmedial line consists of a series of small black dots and dashes. This line is inwardly curved below the position of reniform mark. The outer postmedial line is a series of larger black dots. A series of large black, quadrate dots occurs along the forewing outer margin. The basal line is represented by a single black dot on the costal margin. The antemedial line is evenly convex outward and consists of a series of black dots. The orbicular mark is absent and the reniform mark is a small, black dot. A black spot is present in the median area on the costal margin. The hindwing is usually almost completely suffused with dull brown, although the base of the wing is partially dull white in a few male specimens. The triangular projection on the saccular margin of the male valve is located much nearer the apex of the valve than in binda. This projection is not hooked at the tip as in soror. The vesica is very close to that of binda. However the lower group of spine-like cornuti (in the orientation of the figure) is more diffuse than in binda and some of the spines run upward to the margin of the upper group of larger spine-like cornuti. The vesica of tricolor lacks the ventral diverticulum of soror and the larger spine-like cornuti are not as large nor are the margins of the larger spines serrate as in soror. The female appendix bursae is long and quadrate, points in a caudal direction, and is not bent outward as in binda

Adults have been collected in August, September, and October.

Distribution: Grotella tricolor has nearly the same distribution as binda, although it has not been collected in as many different localities. The species occurs in the Big Bend region of southwestern Texas but has been most commonly collected in the southern and central regions of Arizona. The species has also been collected in Mohave County in western Arizona and across the border in San Bernardino County of southern California. There is little significant variation in this species, although as usual the strength of the black forewing markings is slightly variable between individuals within a population.

Identification Quality: Excellent

Larva: Unknown

Foodplants: Unknown


Grotella tricolor

The orange band in the double postmedial line is very distinctive and tricolor is unlikely to be confused with any other species of Grotella. It might be confused with margueritaria. Grotella margueritaria is a larger species The forewing postmedial line of margueritaria is also double and some dull orange does occur between the two lines. However the dull orange is very light and faint and hardly visible against the cream-white background.

Similar Species

Grotella margueritaria