SERPHOID AND CHALCIDOID PARASITES OF THE HESSIAN FLY 103 



Female. — Length 2 mm. Head a little broader than thorax, viewed from 

 above nearly three times as broad as thick antero-posteriorly, very slightly 

 convex in front and very slightly concave behind, the temples receding from 

 the eye margins and poorly defined; ocelli in a low triangle, the postocellar 

 line much longer than the ocellocular, the latter equal to about twice the diam- 

 eter of an ocellus ; head, viewed from in front, a little broader than high, sub- 

 triangular in outline; malar space appearing nearly equal to height of eye; 

 antennal scrobe very shallow, almost absent ; eyes short oval, with a few very 

 short and inconspicuous cilia ; clypeal area very weakly convergently striated, 

 rest of head with shallow reticulate sculpture which is strongest on the frons 

 and behind the vertex, the vertex very nearly smooth; head posteriorly and 

 anteriorly sparsely clothed with fine pale hairs ; right mandible 4-toothed, left 

 mandible 3-toothed ; labial palpi 3-jointed, maxillary palpi 4-jointed. Antennae 

 slender, slightly thickened apically, 13-jointed, the scape cylindrical, very 



Figure 23. — Merisus cognatus Gahan : A, Adult female ; B, antenna of female. A, x 33. 



nearly as long as the six following joints combined ; pedicel fully twice as long 

 as broad ; first ring joint transverse, minute, the second ring joint also trans- 

 verse, about half as long as broad and at least twice as long as the first ; first 

 funicle joint slender, cylindrical, one and one half times as long as broad, not 

 or very little thicker than the ring joints ; second funicle joint about equal in 

 length to two ring joints and the first funicle joint combined, a little thicker 

 at apex than at base and distinctly a little longer than the third joint ; third 

 funicle joint approximately one fourth longer than broad, the following joints 

 very slightly shorter than or subequal to the third ; club solid, very little 

 thicker than the funicle, nearly as long as the three preceding funicle joints, 

 three times as long as broad, elongate ovate, and terminating in a distinct 

 straight process. Thorax subovate, one and one half times as long as broad, 

 shining, with distinct but very shallow reticulate sculpture which is a little 

 stronger on scutellum than elsewhere; pronotum short, rounded in front, a 

 little narrower than the mesoscutum, almost wholly declivous and nearly 

 smooth; mesoscutum nearly twice as broad as long, the parapsidal grooves 

 weakly impressed anteriorly, entirely effaced posteriorly ; scutellum subconvex, 

 a little shorter than mesoscutum and about as broad as long; axillae broadly 

 separated and sculptured like mesoscutum; propodeum about half as long as 



