452 U. S. NATIONAL MUSEUM BULLETIN 216 



Second tergite and basal 0.5 ± of third tergite mat; metapleurum with weak 

 wrinkles or almost smooth; lower part of trough of pronotum without 

 longitudinal ridges or with only short weak ones. 



15. parvum, new species, in part 



FEMALES 



(The female of formicoides is unknown, but it is placed in the key according to 

 the characters it is presumed to have.) 



1. Middle tibia without an oblique groove on postero ventral side 2 



Middle tibia with a deep oblique groove on posteroventral side. Mellipes 



group (p. 458) 6 



2. Tibiae with long suberect hairs in addition to the short clothing hairs; first 



tergite distinctly punctate, not conspicuously striate; wings always fully 



developed. Cilipes group (p. 454) 3 



Tibiae without long suberect hairs, with only the short clothing hairs; first 

 tergite with strong longitudinal striation, not conspicuously punctate; 

 wings sometimes short or absent. Polymorphum group (p. 456) ... 4 



3. Front and middle coxae black; tooth on hind femur about 0.6 as long as its 



basal width, not followed distally by a notch; intercubitus about 0.4 as 



long as second abscissa of cubitus 1. cilipes, new species 



Front and middle coxae fulvous; tooth on hind femur about 1.4 as high as its 

 basal width, followed distally by a rounded notch that separates it from 

 the ventral ridge on femur; intercubitus less than 0.3 as long as second 

 abscissa of cubitus 2. bicolor (Cresson) 



4. Head about 1.18 as wide across temples as across eyes. 



5. formicoides, new species 

 Head 0.95 to 1.04 as wide across temples as across eyes 5 



5. Head and thorax blackish; basal 0.4 of second tergite with small sparse punc- 



tures, striatopunctate at the extreme base .... 3. pullum, new species 



Head and thorax light brown; basal 0.4 of second tergite longitudinally 



striate and with some indistinct punctures . 4. polymorphum (Cushman) 



6. Abdomen ferruginous, at least beyond the first segment. (0. dichrous is 



variable in this character and runs through both halves of the couplet.) . . 7 

 Abdomen entirely black 12 



7. Femora black 18. atripes (Rohwer) 



Femora ferruginous or fulvous 8 



8. Punctures on mesoscutum dense, in central part of median and lateral lobes 



of mesoscutum separated by less than 2.5 their diameter. 



9. abdominale (Cresson) 



Punctures on mesoscutum sparse, in central part of median and lateral 



lobes of mesoscutum separated by more than 2.5 their diameter .... 9 



9. Hairs on upper half of front side of hind femur long and sparse, the punctures 



from which they arise separated by about 3 times their diameter; trough of 

 pronotum without cross ridges except sometimes at the epomia. 



22. strangaliae (Rohwer) 



Hairs on upper half of front side of hind femur short and dense, the punctures 



from which they arise separated by about 0.8 their diameter; trough of 



pronotum usually with numerous cross ridges 10 



10. Hairs on lower part of front face of hind femur almost as dense as on the rest 



of the femur 16. brevicaudus (Cushman) 



Hairs on lower part of front face of hind femur much sparser than elsewhere, 

 with an almost bald area occupying the lower 0.2 to 0.5 of the femur . . 11 



