This moth was attracted to a blacklight set up in a well-wooded subtropical neighborhood on Sanibel Island. The FW on this moth was measured at 5.9 mm. That is relevant to help resolve its identity. I’ve worked through Klots’ (1) descriptions and keys to the patterns of Microcrambus as well as Bleszynski's 1967 paper on neotropical species (2).

Based on the dull gray-white ground color of the FW, the present moth is a member of what Klots (1) described as a group including the following species in North America: elegans, minor, polingi, discludellus, kimballi, and matheri, along with croesus, at the time not well-studied by Klots. Of these, polingi can be eliminated on range, and elegans eliminated by its distinct pattern. Croesus is large (FW 7.5mm), has a simple terminal line, and large dark mid-dorsal blotches on the FWs (2). See this presumed Central Texas example of croesus.

Among the remaining species, matheri has “all elements (of the subterminal dark and white lines) distinct and clear-cut”(1), unlike the smudged subterminal pattern on the present moth. See this example on MPG.

The distal mid-dorsal mark on minor is “a large, almost black and rectangular patch”(1), unlike the more discrete narrow dark curved lines in the other species and as seen on the present moth. Minor seems to be well-illustrated by several examples on MPG and in this BG example from North Dakota:


Both of the two remaining species, kimballi and discludellus, are described by Klots(1) as very small, with FW lengths of 4.4 to 5.8 mm. Kimballi has white palpi, head, and thorax, with a crenate outer subterminal line. My moth doesn’t share these elements.

For the present moth, all this points to discludellus which is illustrated in two specimens on the BOLD website and is shown on MPG to range up through the FL peninsula. My moth matches that species well except that Klotz indicates it is very small with FW only 4.8 to 5.4 mm. I’m comfortable that my individual is not far outside of that range; I may be measuring the FW slightly wrong.