NORTH AMERICAN TETRASTICHUS — BURKS 569 



Tetrastichus doteni Crawford, Proc. Ent. Soc. Washington, vol. 13, p. 234, 1911. 

 (New synonymy.) 



Iridescent blue-green ; scape sometimes, apices of femora, bases and 

 apices of tibiae, and basal segments of tarsi light yellow or white; 

 darkened areas of tibiae sometimes lighter than dark parts of femora, 

 but generally they are the same color; mesal lobe of metanotum 

 slightly lighter than dorsum of thorax. 



Female. — Length, 1.6-1.8 mm. Antennae inserted at level of ven- 

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

 margin of anterior ocellus ; pedicel and first f unicle segment equal in 

 length, second and third segments equal and each slightly shorter 

 than first, club as long as pedicel and first f unicle segment; length 

 of malar space one-half as great as height of compound eye ; postocel- 

 lar line three times as long as ocellocular. Mesopraescutum as long 

 as wide and bearing three or four rows of bristles at each lateral 

 margin, meson always bare (fig. 19, b) ; submarginal vein of forewing 

 with four or five dorsal bristles; stigmal vein long, slightly more 

 than one-half as long as marginal ; hindwing blunt at apex, fringe at 

 posterior margin one-fourth as wide as wing at hamuli. Surface 

 of propodeum very faintly reticulated, almost smooth, paraspiracular 

 carinae wanting, mesal length of propodeum one-fifth as great as 

 length of mesoscutellum ; spiracles almost contiguous with anterior 

 margin of propodeum; gaster one and one-half times as long as 

 thorax. 



Male. — Length 1.5 mm. Darkened anterior carina of scape one-half 

 as long as scape; f unicle segments semiquadrate and bearing setae 

 only as long as the segments; first segment three-fourths as long as 

 second ; gaster and thorax equal in length ; apex of ninth tergite acute, 

 rather than blunt. 



Type locality. — Urbana, 111. 



Types. — Holotype and allotype in Illinois Natural History Survey 

 collection. 



Hosts. — Microbracon gelechiae (Ashmead), parasitic on Canarsia 

 hammondi Riley ; Microbracon sp. and Apanteles sp. parasitic on vari- 

 ous Coleoptera and Lepidoptera. Specimens have been reared, appar- 

 ently as primary parasites, from Coleophora malivorella Riley and an 

 unidentified lepidopterous miner on arborvitae (probably Argyresthia 

 thuiella (Packard) or Recurvaria thujaella Kearfott). A series was 

 also reared from the cocoons of a coniopterygid, Malacomyza (Aleu- 

 ronia) westwoodi (Fitch) ; another series was reared from the heads 

 of bush clover (Lespedeza) infested with Apion sp. (probably A. 

 decoloratum, Smith) and an unidentified bruchid. The specimens of 

 T. caerulescens in this case, however, probably emerged from the 

 cocoons of some Microgaster parasitic on the weevils. The same may 



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