128 MISC. PUBLICATION" 17 4, U.S. DEPT. OF AGRICULTURE 



IMPORTANCE 



McConnell pointed out that because of the comparatively short 

 life cycle there is ample time in one season for an enormous multipli- 

 cation of the species, and he indicated a belief that it might under 

 certain conditions prove to be an important factor in the control of 

 the fly. Investigations carried on at the Carlisle, Pa., laboratory 

 of the Bureau of Entomology covering a period of 10 years, which 

 were published by Hill and Smith in 1928, showed an average annual 

 parasitization of the spring generation of the fly amounting to only 

 0.11 percent. These figures apparently do not bear out McConnell's 

 hopes, but on the contrary indicate that the species is a nearly neg- 

 ligible factor in the control of the hessian fly. 



Family EULOPHIDAE 



HORISMENUS TEXANUS (Girault) 

 (Fig. 29) 

 Pseudomphale texana Girault, Insecutor Inscitiae Menstruus 4 : 120, 1916. 



DESCRIPTION 



Horismenus texanus differs from all the other parasites of the 

 hessian fly by having a distinct median longitudinal groove running 

 the full length of the scutellum, and by having on the propodeum a 

 narrow, smooth, flat, median area which is bounded on each side by a 

 shallow, slightly depressed, finely punctate area of about the same 

 width as the median area. It differs from other American species of 

 Horismenus except floridanus Ashmead by having the femora metallic 

 like the thorax. From floridanus it differs in that the first tergite 

 (not counting the petiole) constitutes not more than half the length 

 of the abdomen and is quite differently sculptured, while the color of 

 the head and thorax is more metallic. 



Female. — Length 2 to 2.4 mm. Head transverse, about as wide as thorax, 

 and about two and one half times as broad as thick antero-posteriorly ; ocelli 

 in a nearly equilateral triangle, the posterior ocelli about their own diameter 

 from the eye margins ; occiput very slightly concave, finely reticulate-punctate ; 

 temples very narrow ; eyes ovate, subacute ventrally and conspicuously hairy ; 

 vertex and ocellar triangle finely and shallowly reticulated, the area on each 

 side of front ocellus more coarsely and deeply sculptured ; front strongly and 

 closely punctate but with the small triangular area above the transverse fur- 

 row and a narrow, slightly elevated, triangular, medial area originating be- 

 tween the antennae and extending nearly to the transverse furrow, smooth 

 and polished ; face more finely sculptured than the frons ; cheeks weakly 

 reticulated ; mandibles each with three teeth, the inner tooth a little shorter 

 than the others and more or less notched at apex ; labial as well as maxillary 

 palpi 1-jointed. Antennae 10-jointed counting three very minute ring joints, 

 inserted nearly on a line with lower margins of the eyes ; scape slender, a 

 little thicker beyond middle ; pedicel a little more than twice as long as thick, 

 subequal to the first funicle joint plus ring joints ; first funicle joint a little 

 longer than second, the latter a little longer than third which is slightly 

 longer than broad ; club 2-jointed, the basal joint a little broader than the 

 funicle joints and approximately one and one half times as long as broad : 

 apical joint much narrower, conical, and ending in a short process. Thorax 

 not twice as long as broad ; pronotum short, conical, finely sculptured, its 

 apical border polished and separated from the sculptured portion by a raised 

 line from which a fringe of about six long slender hairs originates ; mesonotum 



