Pygarctia spraguei
Sprague's pygarctia

Key Characteristics

Sprague's pygarctia has an average wingspan of 1.2-1.4 inches (3 - 3.6 cm). The thorax and wings are mouse gray in color, with the forewing (i.e., upper wing) having a variable red shaded line along the top and bottom margins of the wing. The head, two lines on the thorax and the abdomen are also red.

Status and Rank

  • State Status: SC
  • State Rank: S2S3
  • Global Rank: G5


County NameNumber of OccurrencesYear Last Observed
Distribution map for Pygarctia spraguei

Updated 5/15/2018. Information is summarized from MNFI's database of rare species and community occurrences. Data may not reflect true distribution since much of the state has not been thoroughly surveyed.


Sprague's pygarctia is found in openings of oak barrens and oak-pine barrens. The species also is associated with prairie, idle/old field, right-of-way, savanna, dry hardwood and forest opening habitats wherever the larval host plant flowering spurge (Euphorbia corollata) is found.

Specific Habitat Needs

Host plant needed in Dry-mesic southern forest, Dry southern forest, Oak openings, Oak barrens, Oak-pine barrens, Pine barrens, Mesic sand prairie, Mesic prairie, Dry-mesic prairie, Dry sand prairie

Natural Community Types


For each species, lists of natural communities were derived from review of the nearly 6,500 element occurrences in the MNFI database, in addition to herbarium label data for some taxa. In most cases, at least one specimen record exists for each listed natural community. For certain taxa, especially poorly collected or extirpated species of prairie and savanna habitats, natural community lists were derived from inferences from collection sites and habitat preferences in immediately adjacent states (particularly Indiana and Illinois). Natural communities are not listed for those species documented only from altered or ruderal habitats in Michigan, especially for taxa that occur in a variety of habitats outside of the state.

Natural communities are not listed in order of frequency of occurrence, but are rather derived from the full set of natural communities, organized by Ecological Group. In many cases, the general habitat descriptions should provide greater clarity and direction to the surveyor. In future versions of the Rare Species Explorer, we hope to incorporate natural community fidelity ranks for each taxon.


The sites at which this species has been documented should be protected and maintained. Adequate and suitable habitat at these sites need to be maintained including sufficient densities of the species' host plant, flowering spurge. Maintenance and long-term preservation of the extant sites and habitats with which this species is associated depends on the promotion of fire (or an equivalent anthropogenic disturbance) as the prime ecological process driving the persistence and establishment of these natural communities. Prescribed burning can be used as a management tool to try to re-establish or replicate natural fire regimes of these systems. In areas where this species or other rare invertebrates occur or are of management concern, burning strategies should allow for ample refugia (e.g., only burning part of the available habitat at a time, burn frequency and intensity, type of fire, etc.) to minimize incidental take or other potential adverse impacts and facilitate effective post-burn survival and/or recolonization. Selective harvesting, mowing, brush cutting and/or other mechanical manipulations can be used in conjunction with or in place of prescribed burning as management tools for maintaining the habitats used by this species. These activities should be conducted in late fall or winter, if possible, to minimize adverse impacts to rare invertebrates. The reduction of ORV traffic by road closure also is recommended in or near known extant sites or areas with potential for the species to minimize adverse impacts to the species and its habitat.

Active Period

Flight from fourth week of May to first week of August

Survey Methods

In Michigan, adults of this species have been found from mid-late May to early August. The best way to survey for this species is by blacklighting at night during the adult flight period, a technique whereby a sheet is stretched across two trees or poles and an ultraviolet light is used to attract moths to the sheet. Moths can be collected directly from the sheet. Insects come to light usually in largest numbers on still, dark, cloudy nights when both temperature and humidity are high. Reports of this species should be documented with a voucher specimen or a good photograph and verification by a species expert.

Page Citation

Michigan Natural Features Inventory. 2007. Rare Species Explorer (Web Application). Available online at [Accessed Aug 16, 2018]


Survey References

Technical References

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