SEEPHOID AND CHALCIDOID PARASITES OF THE HESSIAN ELY 143 

 TETRASTICHUS PRODUCTUS Riley 



Tetrasticlius productus Riley, U.S. Natl. Mus. Proc. (1885) 8: 419, 421, 1886: 

 Amer. Nat. 19: 1104, 1S85 ; Amer. Assoc. Adv. Sci. Proc. (1885) 34: 333, 1886: 

 Cresson, Synopsis of the families and genera of Hymenoptera of America, north 

 of Mexico . . ., p. 246, 1887; Lindeman. Bui. Soc. Nat. Moscou (2) 1: 183, 1887: 

 Marchal, Ann. Soc. Ent. France 66: 81, 1897; Osborn, U.S.Dept.Agr., Div. Ent. 

 Bui. (n.s.) 16: 28, 37, 1898; Dalla Torre, Catalogus hymenopterorum . . ., v. 5. 

 p. 21, 1898; Ainslie, Ent. Soc. Wash. Proc. 10: 14, 1908; Viereck, in Smith, In- 

 sects of New Jersey . . ., p. 639, 1910 ; Viereck, Conn. State Geol. and Nat. Hist. 

 Survey Bui. 32: 454, 1916; Headlee and Parker, Kans. Agr. Expt. Sta. Bui. 

 188 : 109, 1913. 



DESCRIPTION 



As already indicated, Tetrastichus productive, like T. carinatus, 

 may be distinguished from other parasites of the hessian fly by the 

 presence of two parallel grooves on the dorsum of the scutellum. 

 The foregoing description of carinatus will apply to productus 

 except in the following respects : 



Female. — Length 1.75 to 2 mm. There is no distinct carina at the bottom 

 of the frontal depression and the sculpture of the head is a little less distinct 

 than in carinatus. The antennal pedicel is narrower and much shorter than 

 the first funicle joint, about one and one half times as long as thick; funicle 

 joints subequal or successively diminishing very slightly in length, each about 

 twice as long as thick and distinctly longer than the pedicel ; club not thicker 

 than the funicle joints, distinctly 3-jointed, the apical joint terminating in a 

 short spine. Thorax as in carinatus, except that it is a little narrower and 

 the sculpture of the mesoscutum is a little less distinct. The propodeum is 

 a little longer than in carinatus, with a distinct median carina, and with the 

 sculpture consisting of tine deep reticulate punctures, the whole surface dull. 

 Hind coxae outwardly on basal half sculptured like propodeum ; middle spur 

 not quite equal to first tarsal joint. Wings extending barely to apex of 

 abdomen ; submarginal vein with only one erect bristle dorsally ; marginal vein 

 about three times as long as stigmal. Abdomen elongated, distinctly longer 

 than head and thorax, conical, not broader than thorax, the apex acute. Color 

 shining black, the mesoscutum sometimes with a greenish cast ; the abdomen 

 usually more or less metallic ; trochanters, apices of all femora, all tibiae, and 

 all tarsi pale yellow; all coxne and femora, except apices of latter, black. 

 Wings hyaline, venation brown ; antennal flagellum brownish, scape brownish 

 testaceous. 



Male. — Length 1.5 mm. Antennae nearly two thirds as long as the body. 

 10-jointed with one ring joint ; scape slightly compressed, about as in 

 carinatus ; funicle 4-jointed. the joints cylindrical, not vase shaped ; the first 

 funicle joint the shortest, about twice as long as broad ; three following joints 

 subequal and about three times as long as broad; each of the four funicle 

 joints with numerous coarse hairs, the first three with a part whorl of 

 suberect curved setae on the dorsal side at base, none of these hairs, however, 

 being much longer than the joints from which they spring ; the fourth funicle 

 joint apparently without such a whorl of setae, or if present it is less distinct 

 than on the other segments ; club distinctly 3-jointed, not broader than funicle, 

 distinctly hairy, but the hairs apparently not arranged in whorls and not 

 much longer than the segment, the three club joints together not quite so long- 

 as the two preceding funicle joints. Abdomen not longer than the thorax, 

 slightly compressed from the sides, blunt at apex. Color as in the female. 



Described from the type series in the United States National 

 Museum comprising 7 females and 5 males. 



REVIEW OF LITERATURE 



Tetrastichus productus was originally described by Riley in 1885 

 from specimens said to have been reared from overwintering co- 

 arctate larvae of the hessian fly collected at Cadet, Mo. The species 

 has been mentioned frequently by subsequent writers dealing with 



