104 HYMENOPTERA. 



on the flagellam beneath; a short pale yellowish-white 

 parallel line on each side of the face, not running higher 

 than the insertion of the antennae. Thorax : a spot on the 

 tegulffi in front, another on the tubercles, of a pale yellowish- 

 white; the base of the posterior tibiae yellowish-white; the 

 wings subhyaline, the nervures black; the first recurrent 

 nervure uniting with the first transverso-medial nervure; the 

 second recurrent entering the second submarginal cell very 

 near its apex. The metathorax abruptly truncate; a tri- 

 angular enclosed space at its base coarsely rugose with 

 longitudinal furrows. 



There are three small species of these black bees, undis- 

 tinguishable at first sight; on close examination they are 

 found to be distinct species — namely, P. hyalinata^ P, 

 lierfovator and P, riipestris. They may be separated by the 

 following distinctions : the face of P. hyalinata is compara- 

 tively oblong-triangular, the flagellum of the antennae being 

 pale fulvous beneath ; — the spot on each side of the face, in 

 the females, being of an elongate triangular shape. P. ru- 

 jjestris is most closely allied to P. hyalinata, but its face is 

 shorter and rounder, the spots on the face are oblong and 

 parallel ones, and the flagellum beneath almost black. 

 P.^erforator is smaller than either of the foregoing, which 

 agree as to size ; the face is quite as broad as long, and round ; 

 the spots on the face resemble those of P. 'perforator, but the 

 enclosed space at the base of the metathorax is much less 

 coarsely sculptured. 



The species of this genus are difficult to separate ; the pos- 

 session of a good series is absolutely necessary in order to 

 distinguish the specific distinctions with facility. 



Aporus femoralisj Van der Lind. 

 Male. Length 3^ lines. Black : head a httle wider than the 



