24 PEOCEEDINGS OF THE NATIONAL MUSEUM vol. 80 



Reviarks. — Described from two female specimens, the type with 

 only locality data, the paratype collected by C. W. Johnson on July 

 20, 1919. The latter specimen is in the collection of the Boston 

 Society of Natural History. I have also seen a specimen of this 

 species, from Pennsylvania, in the Philadelphia Academy of Natural 

 Sciences. 



14. MACROCENTRUS IMPRESSUS, new species 



Superficially very similar to delicatus, but at once distinguished by 

 the distinct impression at base of first tergite. Structurally most 

 closely related to atratus, differing principally in its entirely yellow 

 color. 



Female. — Length 7.5 mm. Head a little broader than thorax; 

 face medially impressed on upper half; lower part of face with 

 scattered, very shallow punctures ; clypeus convex, truncate at apex ; 

 malar space a little shorter than basal width of mandibles ; eyes large, 

 prominent; summit of vertex but little above level of upper eye 

 margins ; ocelli rather large ; ocell-ocular line less than one and one- 

 half times the diameter of ocellus ; temples and cheeks very narrow ; 

 maxillary palpi long, the longest segment much longer than second 

 segment of antennal flagellum and nearly as long as the first ; anten- 

 nae of type broken. 



Thorax with prescutum strongly convex, prominent; notauli 

 foveolate posteriorly; propodeum entirely finely reticulato-rugulose, 

 most weakly sculptured at base; mesopleura with scattered well- 

 separated punctures on lower half; metapleura smooth; calcaria of 

 posterior tibiae thick; radius arising from much beyond middle of 

 stigma ; radial cell ending well before wing apex ; metacarpus extend- 

 ing the length of second intercubitus beyond apex of radial cell; 

 first discoidal cell very long; first abscissa of cubitus straight, the 

 second nearly half as long as recurrent ; nervulus postf ureal by about 

 half its length; submedian cell with a hairless area apically; basal 

 vein hardly curved; mediella less than twice as long as lower 

 abscissa of basella, the latter much longer than nervellus ; radiellan 

 cell broadening slightly apically. 



Abdomen slightly longer than head and thorax combined; basal 

 impression of first tergite extending beyond line of spiracles; the 

 spiracles about as far from base of tergite as from each other ; first 

 tergite finely longitudinally striate; second longer than broad, com- 

 pletely closely longitudinally aciculate except on the narrow lateral 

 depressed margins, the sides of the raised sculptured part slightly 

 emarginate at the middle; third tergite longer than broad, closely 

 finely aciculate on basal two-thirds; ovipositor sheaths distinctly 

 longer than the body. 



