Parasitic HymeTioptera from, the lUinols River. '2ill 



beinoj the longer; the third segment is scarcely half the 

 length of the second, subopaque and only faintly sha- 

 greened; while the following segments, in marked contrast 

 to the preceding, are all short, impunctate, and shining. 



Hob. — Havana, III. 



Types in the collections of the Illinois State Labora- 

 tory of Natural History and in my collection. 



Described from lU d" specimens taken on floating 

 Lemnaceae in the Illinois River. 



Family ICHNEUMONID.E. 



Cremastus Gravenhorst. 

 Cremastus hartii, sp. n. fFig. 13.] 



$.— Length 6.5 mm.; ovipositor about half the length 

 of the abdomen; antennae 30-jointed, scarcely reaching 

 to the middle of abdomen. Brownish yellow or pale 

 ferruginous; head above, the occiput, the antennae, a 

 large oblong spot on middle mesothoracic lobe anteriorly, 

 the fovea at base of scutellura, axillae, postscutellar band, 

 base of petiole, basal half of second abdominal segment, 

 a small spot on dorsum of fifth and sixth segments, all 

 tarsi and the hind tibiae, black or dark fuscous; wings 

 hyaline, the stigma brown, the veins blackish ; abdomen 

 twice as long as the head and thorax united, compressed 

 from the third segment, the petiole and base of third 

 segment finely longitudinally aciculated and feebly 

 fihagreened; the second segment one half longer than 

 the third, the sixth shorter, the seventh still shorter. 

 (The eighth segment has the basal plates of the ovipos- 

 itor abnormally exserted, giving the tip of abdomen 

 an unnatural appearance.) 



c?.— Length 4.5 mm. Agrees with female except in the 

 usual sexual difference and in C(jlor, the sixth and seventh 

 abdominal segments having a black spot above, while the 

 anterior tarsi and the base of the middle tai-si are pale. 



jSaJ.— Havana, 111.; Washington, D. C; Lexington, Ky. 



Types d" 9 in the collections of the Illinois State 

 Laboratory of Natural History, and in my collection. 



