Synonyms and other taxonomic changes
Eupithecia zygadeniata Packard, 1876
Tephroclystis tenebrescens Hulst, 1900
Eupithecia tenebrescens Taylor, 1907
Packard (1876) recites the length of the FW as 0.50 inch (12.5 mm); wingspan 1.0 inch (ca 25 mm).
Adult - very similar to E. indistincta with longer and more pointed primaries, grayer ground color, smaller discal dot, and numerous, indistinct, oblique cross lines.
The increasingly large set of images from Texas on iNaturalist
show the following consistent marks, most of which are highlighted on this image
-- The thoracic disk is typically uniform gray with three darker dots, two at the front margin, one centered and toward the rear.
-- The abdominal shape is fairly distinctive compared to other species in its Texas range: It is bulbous (wide) at the base and much narrower in the outer 1/3 to 1/2, often showing slightly concave sides in the distal 1/2 in dorsal view. This bulbous abdomen is more conspicuous in females. The abdominal tip is often held somewhat upturned. The abdomen of other Texas Eupithecia is narrower at the base, more uniform in width, and gradually tapered.
-- A thin, shallowly U-shaped black line crosses the rear margin of the first abdominal segment, contrasting with the remainder of the gray abdomen.
-- The 2nd and 3rd abdominal segments (those immediately behind the black crossline; sometimes including the 4th segment) each have a conspicuous black dot on the side.
-- A narrow, whitish gray stripe runs down the center of the abdomen, interrupted by a series of black inverted chevrons on the center of each segment.
-- The forewings have a narrow whitish crenulate (wavy) subterminal line which is complete from the costa to the outer angle; it usually does not form a conspicuous white dot near the outer angle as in E. miserulata.
Most numerous in central Texas, but also ranging (sparsely?) from New Mexico and Colorado to Wyoming and Montana.
March-May (June) in Texas; June-July further north.
Larvae feed on the flowers and seed capsules of Green Lily (Schoenocaulon texanum
; Liliaceae; BG records) and Death Camas (Toxicoscordium [= Zygadenus] nuttallii
in Texas. The larval food plants in other western states are undetermined.
Closely related to E. indistincta
of the northeastern U.S.(1)(3)
but the ranges are apparently widely separated (OK and CA records of that species on MPG are likely erroneous).