NORTH AMERICAN TETRASTICHUS — BURKS 591 



near base), and basal segments of middle and hind tarsi white; front 

 tarsi usually tan, gaster light brown at base. 



Female. — Length, 2.0 mm. Antennae inserted slightly ventrad of 

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

 of anterior ocellus ; all f unicle segments equal in length and each one- 

 eighth shorter than pedicel, club as long as two distal f unicle segments ; 

 postocellar line two and one-half times as long as ocellocular; length 

 of malar space two-thirds as great as height of compound eye ; meso- 

 praescutum with two rows of bristles at each lateral margin; sub- 

 marginal vein of f orewing with two or three dorsal bristles ; metacoxae 

 entirely glabrous; surface of propodeum smooth, paraspiracular 

 carinae absent ; propodeal spiracles large, not touching anterior mar- 

 gin ; mesal length of propodeum one-fifth as great as length of meso- 

 scutellum ; gaster twice as long as thorax. 



Male. — Length, 1.8 mm. Funicle segments with transverse basal 

 enlargements, these bearing setae slightly longer than segments ; gaster 

 and thorax equal in length. 



Type locality. — St. Paul, Minn. 



Types.— U.S.N.M. No. 22132. 



Hosts. — Flat-headed borers, Agrihis arcuatus (Say), Agrilus rubi- 

 cola Abeille, Agrilus champlaini Frost. 



Distribution. — Connecticut, Minnesota, New York, West Virginia. 



TETRASTICHUS THANASIMI Ashmead 



Tetrastichus thanasimi Ashmead, Trans. Amer. Ent. Soc, vol. 21, p. 343, 1894. — 



Gikault, Societas Entomologica, vol. 31, p. 36, 1916. 

 Tetrastichod.es thanasimi (Ashmead) Gujault, Societas Entomologica, vol. 31, 



p. 35, 1916. 



Very dark, shining brown, non-iridescent; antennae, trochanters, 

 apices of femora, bases and apices of tibiae, and basal segments of 

 middle and hind tarsi white or light yellow. 



Female. — Length, 1.1-1.3 mm. Antennae inserted slightly ventrad 

 of level of ventral margins of compound eyes; scape two and one- 

 quarter times as long as pedicel, funicle segments becoming progres- 

 sively shorter, so that third segment is two-thirds as long as first, club 

 as long as pedicel and first funicle segment combined, length of malar 

 space three-fourths as great as height of compound eye ; postocellar line 

 twice as long a9 ocellocular. Mesopraescutum with one or two rows of 

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

 three to five dorsal bristles; marginal vein two and one-half times as 

 long as stigmal vein; apex of hindwing blunt, fringe at posterior 

 margin one-fourth as wide as wing at hamuli. Surface of propodeum 

 smooth, mesal length two-fifths as great as length of mesoscutellum ; 

 paraspiracular carinae wanting ; spiracles separated from anterior mar- 



