(Fig. 5 and 6)

Mutilla Euterpe Blake 1879: 249. Type ♀ (UMSP).

Timulla (Timulla) compressicornis Mickel 1937a: 59, pl. II, fig. 10. Holotype ♂ (NMNH). New synonym.

Remarks. The male-based species Timulla compressicornis Mickel, 1937 is closely related to Timulla barbigera (Bradley, 1916), as both males lack a ventrobasal mandibular tooth and have a Y-shaped pygidial process with the arms of the Y as long as or longer than the stem. The female-based species Timulla euterpe (Blake, 1879) is closely related to the female of T. barbigera, as females of both species have a remarkably similar mesosomal shape in dorsal view and a highly-reduced scutellar scale. Both T. compressicornis and T. euterpe share an overlap in distribution in the eastern United States and are only known from a single sex (Mickel 1937a). Since the publication of Mickel (1937a), both sexes have been collected in Gainesville, Florida and in Kill Devil Hills, North Carolina. Based on the close relationship in morphology with T. barbigera and the two species known from a single opposite sex— T. compressicornis and T. euterpe —coupled with their overlap in distribution in the eastern United States, Timulla compressicornis Mickel, 1937 is here considered a new synonym of Timulla euterpe (Blake, 1879).

Lastly, three male specimens with a nearly entirely black head (vertex partly dark red) and a nearly entirely black mesosoma (pronotum with lateral dark red spot in one specimen) were discovered among the material examined (Fig. 6). Males typically have an orange-red front, vertex, pronotum, mesoscutum, and the scutellum anteriorly, with the remainder of the mesosoma being black (Fig. 5). These two types of color forms of T. euterpe are more or less similar to the color forms present in other species which were formalized with subspecies designations by Mickel (1937a) (i.e., T. dubitata, T. hollensis, T. ocellaria, and T. vagans). Discovery of T. euterpe males with a nearly entirely black head and mesosoma provides additional evidence that the subspecies of Mickel (1937a) are merely color forms within a species.

Material examined (Timulla compressicornis) ( 3 ♂ ). Holotype: USA: Louisiana: Cameron Par.: Johnson Bayou, 24.Aug.1906, J.D. Mitchell (1♂ – NMNH –TypeNo. 50951 U.S. N.M.). Non-type (s): USA: Florida: Alachua Co.: Gainesville, 13.Jul.1948, P.W. Fattig (1♂ – CUIC – PARATYPE Cornell U. No. 1514.2). North Carolina: Dare Co.: Kill Devil Hills, 01–10.Sep.1959, D.G. Shappirio (1♂ – UMMZ).

Material examined (Timulla compressicornis with mostly black head and mesosoma) (3 ♂ ). Non-type (s): USA: Maryland: Calvert Co.: American Chestnut Land Trust, Warrior’s Rest Sanctuary, 38.536633°N 76.519667°W, 08–21.Jul.2008, M. Gates et al., “beach” “ Malaise trap ” (1♂ – EMUS). South Carolina: Barnwell Co.: Aiken, 30–40 mi. S at Fourmile Branch, 16.Jul.1974, F. Howell & R. Matthews, “ Savannah R. Proj. ” “ Malaise trap A” (1♂ – DGMC; 1♂ – EMUS).

Material examined (Timulla euterpe) (2 ♀ ). Non-type(s): USA: Florida: Alachua Co.: Gainesville, 16.May.1926, M.D. Leonard (1♀ – CUIC). North Carolina: Dare Co.: Kill Devil Hills, 05.Jul.1950, K.V. Krombein (1♀ – NMNH). In total, 54♂ and 34♀ of Timulla euterpe (Blake, 1879) were examined (AMNH, AUEM, CUIC, DGMC, EMUS, FSCA, GCWC, INHS, LSAM, MCZ, MEM, MSUC, NCSM, NHMD, NMNH, OSAC, SEC, SFAC, TAMU, TTUZ, UCDC, UCFC, UGCA, UMMZ, UTIC, WIRC).