Stelis coarctatus

Synonyms: Crawford 1916
Microstelis vernalis, Stelis vernalis, possibly Heriades plenum Provancher.

References:
Additions et corrections a la faune Hymenopterologique du Canada, 1888, Vol. 2, by Provancher, pg. 425. Possibly the original description of the male Stelis coarctatus.
Catalogus hymenopterorum: Apidae (Anthophila), 1896 by Dalla Torre, pg. 379. Synonymy with Stelis lateralis.
Proceedings of the Entomological Society of Washington, 1905, Vol. 7, #4: Some Notes on the Provancher Megachilidae by Titus, pg. 162. Synonymy with Stelis lateralis.
Insecutor Inscitiae Menstruus, 1916, Vol. 4, by Crawford, pp. 104 to 106.
North Carolina Agricultural Experiment Station, 1962, Technical Bulletin #152: Bees of the Eastern United States by Mitchell, pp. 43 to 44.
Contributions of the American Entomological Institute, 1965, Vol. 1 #3: The biology of Heriades carinata by Matthews (Dissertation Michigan State University), pg. 1 to 33.
Trap-nesting Wasps 1967 by Krombein, pg. 282.
Great Lakes Entomologist, 2008, Vol. 41, #3 by Wolf and Ascher, pg. 156.
Zootaxa 2017 #4352: Michigan Bees by Gibbs, pg. 101.

Types:
Note:
Provancher’s original description of his Heriades plenum in Additions et corrections a la faune Hymenopterologique du Canada, 1888, Vol. 2, pg. 425 does not mention white marks on male abdominal segments 4 or 5, and fits the description of Stelis coarctatus.

Dalla Torre synonymized Heriades plenum with Stelis lateralis in Catalogus hymenopterorum, 1896, pg. 379, without any remarks.

Titus in Proceedings of the Entomological Society of Washington, 1905, Vol. 7, #4: Some Notes on the Provancher Megachilidae, pg. 162, confirms the synonymy and gives a description as having yellowish marks on 1 to 3, plus a line each side of segments 4 and 5.

Mitchell in North Carolina Agricultural Experiment Station, 1962, Technical Bulletin #152: Bees of the Eastern United States, pg. 43 gives a short description of Heriades plenum and repeats Titus’ description, and also states, “but examination of the type suggests the probability that it is not that species [Stelis lateralis]. It does not quite agree with any of the eastern species of Stelis, but it is possible that it is a variant of one of them, or of some western species.”
So, it is questionable whether Heriades plenum is a synonym of Stelis lateralis or Stelis coarctatus.

Holotype as Heriades plenum or Stelis plena by Provancher, 1888. Type Locality: Ottawa, Ontario. Assumed in Quebec Museum, Quebec City, Laval University. Type #1637.

Holotype as Stelis coarctatus female by Crawford, 1916. Type Locality: Kansas. In the United States National Museum, Smithsonian, Washington, D.C. Type #537070 & 20612. Photos.

Holotype as Stelis vernalis female by Mitchell, 1962. Type Locality: Pender County, North Carolina, Apr 25, 1953. In the United States National Museum, Smithsonian, Washington, D.C. Type #537085. Photos.