204 HYMENOPTERA. 



Hah. Mexico, Ciudad in Durango 8100 feet (Forrer). 



Antennas as long as the body, stout, third joint longer than the fourth, almost bare. 

 Head coarsely and closely punctured, bearing an indistinct fuscous pile ; face flat, the 

 clypeus projecting in the middle. Thorax closely and rather strongly punctured; 

 mesonotal sutures obsolete ; scutellum rather flat, shining, longer than broad, the sides 

 keeled, the top bearing widely set-apart punctures. Metathorax with two transverse 

 arcuate keels, the space between them reticulated, the rest coarsely punctured ; the 

 pubescence silvery-white. Abdomen shining, the petiole laterally keeled; terebra 

 scarcely so long as the petiole. Wings short ; areolet broader than long, the lateral 

 nervures straight. Coxae and trochanters punctured, covered with a silvery pile ; a 

 reddish ring at the base of the hind femora ; anterior tarsi, tibiae, and the apices of the 

 femora, dirty white in front. 



The short ovipositor separates C. nivalis from the rest of the black-legged species ; 

 the obsolete parapsides form another distinctive character. 



5. Cryptus argentifrons. 



Niger ; tibiis, tarsis anterioribus apiceque tarsorum posticorum, albis ; abdomine rufis, basi et apice nigris ; alis 



fere hyalinis, nervis et stigmate nigris. 3 . 

 Long. 12 millim. 



Hab. Mexico, Northern Sonora (Morrison). 



Antennae nearly as long as the body, stout, densely and shortly pilose ; the third joint 

 a little longer than the fourth. Head closely punctured all over, covered with a silvery- 

 white pubescence ; a large roundish flat tubercle below the antennae ; clypeus project- 

 ing, more shining than the rest of the head, its apex and the inner orbits dirty white. 

 Thorax densely punctured, covered with a silvery-white pubescence ; mesonotal sutures 

 deep. Scutellum shining, punctured, the punctures wide apart ; the sides at the base 

 keeled. Metathorax covered with long silvery- white hair ; a short, blunt tubercle at the 

 side. Abdomen longer than the head and thorax together ; petiole obsoletely keeled 

 laterally, shining, the top a little depressed at the base ; genital organs large, black, 

 minutely punctured. Legs longish ; coxae punctured, covered with longish silvery-white 

 hair. The anterior femora are white in the middle in front ; the tibiae and tarsi almost 

 wholly white; the metatarsus and the apical joint of the hind tarsi are white. Areolet 

 moderate, the lateral nervures converging above. 



Allied to C. albitarsis, Cresson. 



b. Legs red. (Species 6.) 



6. Cryptus sodalis. 



Niger ; abdomine, femoribus, tibiis tarsisque, rufis ; alis hyalinis. 

 Long. 10 millim. ; terebra 5 millim. 



Hab. Mexico, Northern Sonora (Morrison). 



