Key to eastern US Crematogaster

This worker key is based on: Buren, W. F. 1968. A review of the species of Crematogaster, sensu stricto, in North America (Hymenoptera, Formicidae). Part II. Descriptions of new species. Journal of the Georgia Entomological Society. 3:91-121.

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1

 * Thoracic dorsum covered with distinct, strong, vermiculate rugae; a small, dark colored, arboreal species usually found only in cypress swamps; distribution possibly co-extensive with the bald cypress in southern U.S. (type specimens mislabeled as to locality, not found in California) . . . . . Crematogaster vermiculata


 * Thoracic dorsum without vermiculate rugae, or if faintly present on front of pronotum and base of epinotum, then not found in this habitat . . . . . 2

2
return to couplet #1
 * Pronotum rugose on each side and with a median, smoother sulcus; when seen from the front, the high, median mesonotal carina may be seen through this sulcus almost like a gun sight; a small, dark colored, arboreal species, found nesting in live-oaks and other trees along the southern Texas gulf coast and on into Mexico. . . . . . Crematogaster rifelna


 * Pronotum without this configuration . . . . . 3

3
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 * Epinotal spines very short and distinctly in curved; thoracic dorsum smooth to weakly punctate, a small arboreal species common throughout the southeastern states from Texas to the Carolinas . . . . . Crematogaster ashmeadi


 * Without this combination of characters . . . . . 4

4
return to couplet #3
 * Pubescence suberect on at least head and thorax; erect hairs slender and numerous on thorax and gaster . . . . . 5


 * Pubescence appressed on head, thorax, and gaster; erect hairs either rather sparse on thorax and gaster or if numerous then somewhat bristle-like in appearance. . . . . . 6

5
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 * Pubescence suberect on head and thorax only; thorax smooth or faintly punctate; nests in large variety of semi-arboreal situations in or near swamps, salt marshes, rivers, and streams; common throughout southeastern U. S., reaching Texas, Missouri, Indiana, and New Jersey . . . . . Crematogaster clara (= Crematogaster laeviuscula)


 * Pubescence suberect on gaster and legs as well as head and thorax; thorax usually with some distinct rugae; often nests in logs and fallen branches in marshy situations; confined to the east coast from New Jersey to Georgia . . . . . Crematogaster pilosa

6
return to couplet #4
 * Epinotal spines very long and with heavy bases, inclosing a smoothly parabola-like curve when seen from above; base of epinotum usually smooth or only feebly sculptured; common in peninsular Florida and in coastal salt-grass marshes to the Carolinas and Alabama; often builds large carton nests . . . . . Crematogaster atkinsoni


 * Epinotal spines of moderate length and not inclosing a smoothly parabola-like curve; base of epinotum usually distinctly sculptured; carton nests rarely or never constructed . . . . . 7

7
return to couplet #6
 * Erect hairs on thorax confined to a clump of one to several, long, flexuous setae on each shoulder of the pronotum . . . . . 8


 * Erect hairs on thorax numerous and evenly covering nearly the entire dorsum . . . . . 9

8
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 * Sides of pronotum and dorsum of pro - and mesonotum smooth and shining; epinotal spines usually straight; small incipient colonies often in oak galls and twigs, large colonies in tree trunks and logs; common in central Texas, occurring also in Mexico, Oklahoma, and Louisiana; no authentic records known east of Mississippi River . . . . . Crematogaster laeviuscula


 * Sides of pronotum usually distinctly punctate and thoracic dorsum striate; epinotal spines often sinuate; nests under rocks and logs; sometimes doing appreciable injury to woodwork and timbers in houses; common in northeastern states and southern Canada, reaching Georgia through the Appalachians, Arkansas in the Ozarks, and west through the north central states and south to New Mexico in the Rockies . . . . . Crematogaster cerasi

9
return to couplet #8
 * Wide ranging and exhibiting some regional variation: Thoracic dorsum punctate; erect hairs usually of approximately equal length on all parts of thorax; nests in the ground and tends root aphids and coccids; abundant in southern Great Plains area, less numerous but well distributed through the southeastern states, and south into Mexico, and west to Arizona . . . . . Thoracic dorsum rugose or striate; erect hairs very short on mesonotum; nests under rocks and logs; common in northeastern states and southern Canada, reaching south through all of the eastern states to the southern tier, and west to the Great Plains: . . . . . Crematogaster lineolata