Pseudomyrma nigropilosa Emery 1890:62 Pseudomyrmex nigropilosus (Emery) Systematic studies on Pseudomyrmex acacia-ants (Hymenoptera: Formicidae: Pseudomyrmecinae) Ward, Philip S. Journal of Hymenoptera Research 1993 2 117 168 4P4FP 292165 (Emery 1890) Emery 1890 Insecta Formicidae Pseudomyrmex GBIF,CoL Animalia Hymenoptera 43 159 Arthropoda species nigropilosus  (Fig. 7)    Pseudomyrma nigropilosa Emery 1890:62. Syntype workers, Liberia, Costa Rica( A. Alfaro) ( MCSN,  MHNG) [Examined],  Pseudomyrmex nigropilosus (Emery); Kempf 1958:453.  Worker diagnosis. With the traits of the P. gracilisgroup (see couplet 6 of key) and the following more specific features. Head longer than broad (Cl 0.84-0.90); anterior margin of median clypeal lobe convex, conspicuously protruding; dorsolateral margination of pronotum usually blunt; mesonotum more steeply inclined than basal face of propodeum; petiole relatively robust (PLI 0.69- 0.77) with a short anterior peduncle (Fig. 7, 53); head and mesosoma densely punctulate to coriarious-imbricate, and subopaque; standing pilosity conspicuous on most of the body including the outer faces of the tibiae, consisting largely of black hairs, those on the petiole and propodeum long (> 0.20 mm) and curved. Color varying from concolorous orange-brown to bicolored orange and black to (western Mexico) predominantly black with orange mottling on the head, mesosoma, and appendages.  Taxonomic comments. - Among the Pseudomyrmexspecies recorded from swollen-thom acacias, P. nigropilosusis easily identified by its elongate eyes and head (REL 0.55-0.59, Cl 0.84- 0.90), short petiole (PLI 0.69-0.77), and conspicuous black pilosity (Fig. 7). Kempf (1958)provides further descriptive details.  Distribution and biology. - P. nigropilosusis found from Nayarit, western Mexico to Guanacaste Province, Costa Rica, and is restricted to nesting in swollen-thom acacias (including Acacia collinsii, A. cornigeraand A. hindsii). It is a member of the P. gracilisgroup and therefore not closely related to the principal group of acacia-ants ( P. ferrugineusgroup). Janzen (1975)points out that P. nigropilosusis essentially a parasite of the Pseudomyrmex/ Acaciamutualism. It occupies abandoned or otherwise uninhabited plants and reaps the benefits of this association without protecting the acacia from herbivores or competing plants. Additional information about the ecology of this species is given in Janzen (1975). 1416640676 MCSN A. Alfaro Costa Rica Liberia 43 159 syntype 1416640683 MHNG A. Alfaro Costa Rica Liberia 43 159 syntype