Crematogaster rifelna

Identification
Key to Crematogaster of the eastern United States

Distribution based on Regional Taxon Lists
Nearctic Region: United States. Neotropical Region: Mexico.

Nomenclature

 *  rifelna. Crematogaster (Crematogaster) rifelna Buren, 1968b: 96 (w.q.m.) U.S.A.

Worker
Length about 3 to 3.6 mm.

Head, excluding mandibles, a little broader than long, with convex sides and posterior border straight or slightly excised in the middle. Scapes not reaching posterior corners in largest workers, barely surpassing them in small specimens. Humeri of pronotum strong and marked by rugae. Mesonotal carina strong and sharp, especially in front. Anterior to this carina on the pronotum is a distinct, rather smooth, median impression. Thus when the pronotum is viewed in front, the sharp mesonotal carina may be seen through this impression almost like a gun sight. Promesonotum somewhat flattened above in profile. Mesonotal declivity present but strongly angled. Epinotal spines straight, short, a little shorter than interbasal distance, parallel or feebly diverging, directed somewhat upward as well as backward, often with a little impression on base of epinotum just before base of each spine. Petiole with rounded sides seen from above. Hemilobes of postpetiole broad and rounded.

Genal striae very fine and closely set but distinctly etched and carried well past the eyes. Front and all of the rear of the head smooth and shining. Front and dorsum of pronotum irregularly rugose on the sides, finely striato-punctate toward the middle and the median impression usually shining. Sides of pronotum finely striato-punctate, smooth in the oblique impressions. Mesonotum finely striato-punctate. Mesopleura punctate. Metapleura mostly punctate below, striate above. Base of epinotum with strong, straight longitudinal striae, declivity smooth and shining. Postpetiole with faint, fine punctures.

Pubescence rather long, appressed on all parts but scapes, there suberect. Erect hairs not fine, several present on shoulders of pronotum and a few also at rear of mesonotum; on gaster confined mostly to the usual rows near posterior borders of the segments.

Queen
Length about 7 mm.

Head, excluding mandibles, broader than long, somewhat broader •behind than in front, with convex sides and straight or slightly excised posterior border. Scapes far short of reaching hind corners, reaching only to about level of lateral ocelli. Ocelli small. Head much broader than thorax. Mesoscutum a little longer than broad. Scutellum wider than long. Epinotal spines very short, less in length than diameter of their bases. Postpetiole with distinct if feeble impression for its entire length; without spiracular angles.

Clypeus distinctly convex in the middle, all densely striate; no median shining streak. Genae very densely striate (7 striae per 0.1 mm.), this sculpture carried well past the eyes. Rest of head smooth and shining. Pronotum finely punctate, smooth only at rear. Mesosternal sides striato-punctate, mesopleura with a few striae or smooth and shining. Metapleura striate and with fine intercalated punctures. Sides of epinotum striate. Base of epinotum with long longitudinal striae and rugae. Sides of petiole finely punctate. Postpetiole smooth and shining above.

Pubescence short and appressed on all parts. Erect hairs rather sparse on all parts.

Concolorously black. Wing veins and stigma brown.

Concolorously black.

Male
Length about 3 mm.

Basal funicular joints slightly broader than long. Head rather elongate and with very convex posterior border. Ocelli small, the vertex at rear border of head. Thorax a little broader than head. Mesoscutum a little broader than long. Scutellum without trace of lateral impressions, shaped, therefore, as in the female.

Head weakly punctate, shining. Mesoscutum finely striate, shining only on front of parapsides. Pronotum shagreened, subshining, smooth at rear. Mesosternal sides weakly striato-punctate, mesopleura striate in an oblique streak. Metapleura weakly striato-punctate. Sides of epinotum shallowly punctate. Base of epinotum smooth and shining. Pubescent hairs short, suberect on head and thorax, appressed on gaster. Only a few erect hairs present.

Concolorously black. Wing veins very pale yellow.

Additional References

 * [[Media:Buren 1968b.pdf|Buren, W. F. 1968b. A review of the species of Crematogaster, sensu stricto, in North America (Hymenoptera, Formicidae). Part II. Descriptions of new species. J. Ga. Entomol. Soc. 3: 91-121 PDF]]