NORTH AMERICAN TETRASTICHUS BURKS 547 



TETRASTICHUS AENEOVIRIDIS (Girault), new combination 



Trichaporus aeneoviridis Girault, Can. Ent., vol. 44, p. 75, 1912. — Frison, 

 Bull. Illinois Nat. Hist. Survey, vol. 16, p. 223, 1927. 



Bright iridescent green, with occasional purple reflections; legs 

 (except bases of coxae) entirely light yellow or white; antennae and 

 area of head around mouthparts tan or yellowish. 



Female. — Length, 1.8 mm. Apex of scape reaching level of vertex ; 

 second funicle segment slightly longer than first, third equal to first; 

 mesopraescutum with four or five bristles at each lateral margin, 

 median groove vague, almost obliterated; one dorsal bristle on sub- 

 marginal vein of f orewing ; hindwing blunt at apex ; surface of pro- 

 podeum shagreened, paraspiracular carinae present, spiracles sepa- 

 rated from anterior propodeal margin by a space equal to diameter 

 of spiracle. 



Male . — Unkno wn . 



Type locality. — Centralia, 111. 



Types. — Lectotype, paratypes, and metatypes in Illinois Natural 

 History Survey Collection; paratypes, U.S.N.M. No. 12200. 



Host. — This species was originally said to be a primary parasite 

 of the larva of the apple-tree tent caterpillar, MaJacosoma americatia. 

 (Fabricius), but the insectary records in the Illinois Natural History 

 Survey show that the specimens came from syrphid puparia. 



Distribution. — Illinois. 



TETRASTICHUS DIARTHRONOMYIAE Gahan 



Tetratichus diarthronomyiae Gahan, Proe. Ent. Soc. Washington, vol. 25, p. 65, 

 1923.— Hamilton, Maryland Agr. Exp. Stat. Bull. 269, p. 23, 1924. 



Shining black or very dark brown, sometimes faintly iridescent 

 bluish or greenish ; antennae usually, trochanters, bases and apices of 

 femora, tibiae, and basal segments of middle and hind tarsi white or 

 light yellow. 



Female. — Length, 1.0-1.5 mm. Antennae inserted at level of ven- 

 tral margins of compound eyes ; apex of scape reaching level of ante- 

 rior ocellus, first funicle segment three-quarters as long as second, 

 third as long as first, club slightly more than twice as long as first 

 funicle segment; length of malar space two-thirds height of com- 

 pound eye; postocellar line twice as long as ocellocular. Mesoprae- 

 scutum slightly wider than long and bearing three bristles at each 

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

 apex of hindwing acute, fringe at posterior margin one-half width 

 of wing at hamuli. Surface of propodeum shagreened, mesal length 

 one-fifth length of mesoscutellum, both median and paraspiracular 

 carinae present; propodeal spiracles near to but not quite touching 

 anterior margin ; gaster one and one-half times as long as thorax. 



