192 Illinois State Laboratory of Natural History 



or wrinkled, pleurae finely aeiculate and rufous in color. The 

 parapsidal grooves and median groove are broad and very deep 

 near the scutellura, but become narrower and shallower as they 

 extend forward; the parapsides extend to the collar, but the 

 median groove disappears on reaching the posterior ends of the 

 two parallel lines extending back from the collar. The lateral 

 grooves* are very distinct. Scutellum bifoveate, coarsely sculpt- 

 ured, and remarkable for being much drawn out posteriorly. 

 The length of the scutellura is nearly equal to the distance 

 from the scutellum to the collar. Abdomen entirely yellow- 

 rufous, 2d segment occupying about one half of the dorsal sur- 

 face, 3d segment about two thirds as long as the 2d, follow- 

 ing segments very narrow; surface polished, impunctured. 

 Feef^ including coxae, entirely yellow-rufous. Wings hyaline 

 or very slightly smoky, radial nervure very distinctly bowed, 

 the tip being thrown towards the costa; 1st and 2d transverse 

 nervures very heavy, the usual dark stain at the base of the 

 radial nervure present, areolet medium. 



Described from a single female taken by sweeping in a 

 wheat field 20th May, 1884. Accessions number, 1881. Illinois. 



Gall unknown. 



Genus Antistrophus Walsh. 



A. silphii n. sp. 



Galls. — Abrupt sub-globular swellings from 1 to If 

 inches in diameter at the tips of the stems of Silphinm integ- 

 rifolinm and perfoJiatuni (Plate IX., Fig. 1). The inner por- 

 tion of the gall is made up almost entirely of a rather dense 

 pithy material that cuts with some difficulty. Interspersed 

 through the gall are numerous oval larval cells, and also open 

 spaces or cavities that do not contain insects. (Plate IX., 

 Fig. 2.) The larval cells are not woody, as is usually the case 

 in cynipidous galls, but their walls are of pith like the sur- 

 rounding gall substance. 



* The short grooves starting on the mesothorax at a point near 

 the outer angles of the scutelhim and extending outside of the parap- 

 sides to a point about opposite tiie bases of the wings, I shall term 

 lateral grooves in these destriptions to distinguish them from the 

 other lines of the mesothorj^x. 



