NORTH AMERICAN TETRASTLCHUS — BURKS 537 



Head and thorax shining black ; gaster almost entirely white, brown 

 at dorsolateral margins ; bases of coxae, anterior and middle femora 

 partly, and apical segment of each tarsus brown, other parts of legs 

 white. 



Female. — Length, 1.8 mm. Pedicel two-thirds as long as first funi- 

 cle segment; second one-third longer than first, third slightly longer 

 than first, club as long as first and second segments combined. Meso- 

 praescutum two-thirds as long as wide and bearing one bristle at 

 each lateral margin; submarginal vein of forewing with one dorsal 

 bristle; apex of hindwing acute, fringe at posterior margin almost 

 as wide as wing at hamuli. Mesal length of propodeum two-fifths as 

 great as length of mesoscutellum, mesal length of propodeum greater 

 than mesal length of metanotum ; propodeum shagreened, paraspirac- 

 ular carinae present, propodeal spiracles not quite touching anterior 

 margin ; gaster more than twice as long as thorax. 



Male. — Unknown. 



Type locality. — Glenn Dale, Md. 



Type.— U.S.N.M. No. 19990. 



Host. — Unknown. 



Distribution. — District of Columbia, Maryland. 



TETRASTICHUS AINSLIEI Gahan 



Figure 20, h 



Tetrastichus ainsliei Gahan, Proc. U. S. Nat. Mus., vol. 53, p. 214, 1917; U. S. 



Dept. Agr. Misc. Publ. 174, p. 144, 1933. 

 Neomphaloidella mediogutta Girault, Ent. News, vol. 28, p. 255, 1917. (New 



synonymy. ) 



Head and thorax very dark brown or black; antennae, legs (except 

 bases of coxae), and base of abdomen white; apex of abdomen and 

 darkened parts of legs brown, abdomen sometimes almost entirely 

 white. 



Female.— Length, 1.2-1.5 mm. Antennae inserted slightly dorsad 

 of level of ventral margins of compound eyes ; apex of scape reaching 

 level of vertex, second funicle segment slightly longer than first, club 

 as long as two apical funicle segments combined; length of malar 

 space three-fifths height of compound eye. Only one pair of 

 praescutal bristles present; mesopraescutum wider than long; sub- 

 marginal vein of forewing with one dorsal bristle ; hindwing acute at 

 apex, fringe at posterior margin one-half width of wing at hamuli. 

 Surface of propodeum shagreened ; mesal length of propodeum one- 

 third maximum length of mesoscutellum; both median and para- 

 spiracular carinae present on propodeum; propodeal spiracles near to 

 but not quite touching anterior margin; gaster from one and one- 

 quarter to one and one-half times as long as thorax. 



53079S — 43 3 



