Alypiodes bimaculata (Herrich-Schäffer)
Diagnosis: The black, elongate forewings with yellow-white patches before, between, and beyond the orbicular and reniform marks and the blue stripe running through the center of the reniform mark are distinctive. The first yellow patch consists of a elongate triangle pointed toward the base of the wing and terminanting on the inner side of the orbicular mark. A quadrate yellow patch is present between the orbicular and reniform marks. The orbicular mark is round, although the top and bottom ends are cut off and merge with the surrounding black of the forewing. The reniform consists of a wide black bridge between the black costa and the black remainder of the forewing. A slightly curved blue line runs through the central of the reniform mark, although the line may not be apparent unless the light is correctly positioned. Finally an irregularly ovate yellow patch occurs between the reniform mark and the postmedial line. The rest of the forewing is dull black. The ventral forewing surface recapitulates the dorsal surface except that the triangular, basal yellow patch is much weaker, sometimes nearly absent. The hindwing is black, although in most specimens there is a hint of a yellow discal spot. The size of the spot is variable between specimens being quite conspicuous in some specimens to absent in others. The ventral hindwing is the same as its dorsal surface except that the yellow spot is stronger and larger. A row of white scales occurs along the posterior margin of the eye. The prothoracic tibia is covered with brown scales with the orange tufts found in Alypia. Wing length: mean = 20.26 mm, standard deviation = 1.31 mm, n = 10.
Distribution: Alypiodes bimaculata occurs in
the southwestern United States and southward throughout most of Mexico.
The species has been collected commonly in most of New Mexico, southern
and eastern Arizona, and in southern Colorado. Curiously bimaculata
has not yet been collected in western Texas. Alypiodes bimaculata
is a variable species. In particular the size and shape of the yellow
patches in the forewing and hindwing are variable, sometimes relatively
small, but in some cases quite large. The yellow spot in the hindwing
is particularly variable. The yellow patch is usually a small yellow,
diffuse patch in most species, but in a few specimens it can be larger,
and in one specimen even appears double. A few specimens lack a yellow
spot altogether. Mexican specimens seem to have larger yellow spots in
the hindwings than those from the USA on average. Females tend to be larger
than males on average. The species is also variable in size; the largest
female I have seen is 23.5 mm in wing expanse from base to apex, while
the smallest male is only 13.3 mm.
Identification Quality: Excellent
Although Alypiodes bimaculata has maculation similar to the species of Alypia, it is more than twice as big from wing tip to wing tip.
No Similar Species