NORTH AMERICAN TETRASTICHUS — BURKS 541 



long as ocellocular. Mesopraescutum as wide as long and bearing two 

 bristles at each lateral margin ; submarginal vein of f orewing with one 

 dorsal bristle ; apex of hindwing acute, fringe at posterior margin one- 

 half as wide as wing at hamuli. Mesal carina of propodeum wanting 

 or only faintly indicated, paraspiracular carinae wanting, surface of 

 propodeum smooth or very faintly roughened, mesal length of 

 propodeum one-fourth length of mesoscutellum ; propodeal spiracles 

 almost touching anterior margin ; gaster one-third longer than thorax. 



Male. — Length, 1.0-1.2 mm. Scape three times as long as pedicel; 

 funicle segments bearing conspicuously long bristles near bases, first 

 funicle segment equal in length to pedicel, second segment one-eighth 

 longer than first, third and fourth equal and each one-eighth longer 

 than second, club one-fifth longer than scape ; gaster slightly shorter 

 than thorax. 



Type locality. — Urbana, 111. 



Types.— U.S.N.M. No. 56241. 



Described from the female holotype, male allotype, and many male 

 and female paratypes reared from oakleaf gall of N euroterus verru- 

 carwm, (Osten Sacken), June 25, 1927, by W. V. Balduf ; many addi- 

 tional specimens reared May 11-June 17, 1927, and May 1-26, 1928. 

 All specimens reared from galls collected from the same tree. 



TETRASTICHUS DYRUS. new species 



Figube 16, h; 20, e 



Black; apices of antennal scape and pedicel, flagellum, sometimes 

 apices of coxae, bases and apices of femora, tibiae, and basal three 

 segments of tarsi light yellow or white ; antennal flagellum and tibiae 

 sometimes very slightly darkened, femora occasionally almost entirely 

 yellow. 



Female. — Length, 0.9-1.1 mm. Antennae inserted at level of ventral 

 margins of compound eyes, apex of scape not quite reaching level of 

 anterior ocellus, pedicel enlarged at apex and slightly longer than first 

 funicle segment, each funicle segment shorter and very slightly wider 

 than segment proximad of it, club long, relatively slender, three times 

 as long as third funicle segment (fig. 16, h) ; length of malar space 

 two-thirds as great as height of compound eye ; postocellar line twice 

 as long as ocellocular. Mesopraescutum with two long bristles at each 

 lateral margin ; submarginal vein of f orewing with one dorsal bristle, 

 marginal vein four and one-half times as long as stigmal; apex of 

 hindwing acute, fringe at posterior margin two-thirds as wide as wing 

 at hamuli. Surface of propodeum obscurely reticulated, paraspiracu- 

 lar carinae absent, well-marked oblique ones usually present, spiracle 

 almost contiguous with anterior margin of propodeum ; median length 



