540 PROCEEDINGS OF THE NATIONiAiL MUSEUM vol. 93 



Black, or sometimes very dark brown, with iridescent blue or blue- 

 green reflections; antennae yellow and brown ; trochanters, basal three- 

 fourths of femora, and often hind tibiae brown; apices of femora, 

 front and middle tibiae, and tarsi white or yellow ; abdomen sometimes 

 brown at base. 



Female. — Length, 1.1-1.5 mm. Antennae inserted at level of ventral 

 margins of compound eyes; scape broad and short, only slightly more 

 than twice as long a9 pedicel, apex of scape not reaching level of 

 anterior ocellus, first funicle segment slightly shorter than second or 

 third, latter two each slightly shorter than pedicel, club twice as long 

 as pedicel; malar space one-half height of compound eye; postocellar 

 line three times as long as ocellocular. Mesopraescutum one-third 

 wider than long and usually with one row of bristles at each lateral 

 margin, a partial second row sometimes present; marginal vein of 

 forewing with two dorsal bristles; apex of hindwing blunt, width of 

 fringe at posterior margin one-third width of wing at hamuli ; scutellar 

 grooves vague anteriorly. Thorax wide, abdomen elongate and nar- 

 row; propodeum extremely short so that abdomen appears broadly 

 joined to thorax; surface of propodeum almost smooth, median carina 

 vague or wanting entirely; mesal length of propodeum one-fifth 

 length of mesoscutellum ; propodeal spiracles large, almost contiguous 

 with anterior margin; gaster long, slender, twice as long as thorax. 



Male. — Length, 0.8-1.1 mm. Scape with a darkened anterior carina 

 two-thirds as long as scape; first funicle segment two-thirds as long 

 as second, following three segments equal in length, funicle segments 

 monilif orm and without long setae ; club almost three times as long as 

 fourth funicle segment; gaster equal in length to thorax. 



Type locality. — Maxwell, N. Mex. 



Types.— U.S.N.M. No. 20446. 



Hosts. — Eggs of tent caterpillars, Malacosoma fragilis Stretch, M. 

 americana (Fabricius), M. disstria Huebner. 



Distribution. — Delaware, Idaho, Massachusetts, Nebraska, New 

 Mexico, New York, Oregon, Pennsylvania. 



TETRASTICHUS BALDUFI, new species 



Brown; antennae, trochanters, bases and apices of femora, tibiae, 

 basal segments of tarsi, and usually spot at base of gaster white or 

 yellowish ; base of gaster may be tan, rather than yellow or white. 



Female. — Length, 1.0-1.4 mm. Antennae inserted at level of ventral 

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

 ocellus; first funicle segment slightly shorter than second, third and 

 second equal in length; club two and one-half times as long as third 

 funicle segment; length of malar space one-half height of compound 

 eye; malar suture curved; postocellar line one and one-half times as 



