58 MISC. PUBLICATION 17 4, U.S. DEPT. OF AGRICULTURE 



IMPORTANCE 



This species is probably of slight importance as a parasite of the 

 hessian fly. In investigations extending over a period of 10 years, 

 Hill and Smith found an average parasitization by it in the Eastern 

 States of 0.04 percent. Its polyphagic habits, although tending to 

 insure its survival, tend to reduce its efficiency as a primary parasite 

 of any given species through dissipation of its efforts and to increase 

 the likelihood of its doing more harm than good by attacks upon 

 other beneficial species. Thus, while accomplishing some good as a 

 parasite of the hessian fly, jointworm, wheat stem sawfly, and perhaps 

 other species, this parasite is by no means an unmixed blessing, as 

 shown by Muesebeck and Dohanian who record the rearing of hun- 

 dreds of specimens of it from cocoons of Apanteles melanoscelus, one 

 of the most important parasites introduced to combat the gypsy moth. 



CALOSOTA METALLICA Gahan 



(Fig. 13) 



Calosoter metallicus Gahan, U.S. Natl. Mus. Proc. 61 (art 24) : 16, 1922. 

 Calosota metallica Packard, U.S. Dept. Agr. Tech. Bui. 81 : 14, 1928. 



DESCRIPTION 



Calosota metallica is related to Eupelmus allynii, but it may be dis- 

 tinguished from that species, as well as from other eupelmids attack- 

 ing the hessian fly, by the scutellum, which is large, strongly convex, 

 and has a broad base on the mesoscutum, and by the axillae, which are 

 small and very widely separated. It also differs by having the 

 mesoscutum only very slightly impressed medially, and by being 

 more uniformly metallic in color. 



Female. — Length 2.15 to 3.5 mm. Head transverse, as broad as thorax, 

 about twice as broad as thick at the middle, weakly concave behind, with rather 

 weak reticulate sculpture which is strongest on the frons ; ocelli in a slightly 

 obtuse angle ; the postocellar line nearly twice as long as ocellocular, the latter 

 no longer than the diameter of an ocellus ; scrobes deep, nearly as broad above as 

 below ; malar space equal to half the eye height ; eyes moderately large, forming 

 a short ellipse, and clothed with very short inconspicuous pile : clypeus not 

 separated from face posteriorly but limited laterally by a very delicate groove, 

 its anterior margin straight or very slightly concave ; mandibles each with three 

 acute teeth ; labial palpi 3-jointed ; maxillary palpi 4-jointed, the apical joint 

 about as long as the three basal joints combined, broadest at the middle, and 

 with a small tubercle or budlike projection at the broadest point. Antennae 

 strongly clavate, rather short ; scape cylindrical, not reaching to front ocellus ; 

 pedicel a little longer than the ring joint and first funicle joint combined ; ring 

 joint subquadrate ; funicle rather slender at base, increasing in thickness toward 

 apex and clothed with moderately long hairs ; first funicle joint about one and 

 one half times as long as broad ; second about twice as long as broad ; third 

 and fourth subequal in length to the second but a little broader ; fifth subequal 

 in length to first but broader ; sixth subquadrate ; seventh slightly transverse ; 

 club much broader than the funicle joints, 3-jotnted, broadly ovate ; the first 

 three funicle joints apparently without elongate sensoria, fourth and fifth with 

 2 sensoria each, sixth and seventh with 4 each, and the club joints with about 

 12 each, the sensoria on the short ultimate and penultimate joints of the club 

 extending from base to apex of the segment. Prothorax short, conical, far 

 below the level of the mesoscutum ; mesoscutum and scutellum strongly sculp- 

 tured, the former very slightly depressed on its disk, its sculpture consisting 

 of shallow, more or less irregularly shaped areas set off by raised lines, the 

 scutellum with similar sculpture, but with the areas more minute and elongate, 

 giving a more or less longitudinally lineolate appearance ; postscutellum distinct, 

 extending to the apex of propodeum ; axillae very small and widely separated ; 



