24 Rev. T. A. ^Marshall's Monograf)h of 



a merely cursory inspection, for one of the smaller Opii, 

 {pygnurator, etc.), it is sufficient to observe the length of 

 the petiole. Only one species occurs in the British fauna, 

 and another in America. The so-named Toi'itrcs {Trionyx) 

 rapie, Curtis (Farm. Ins. 73), and figured in Mcintosh 

 (Book of the Garden, ii, 104), belongs to the genus 

 Aphidius. 



Toxares deltigcr, Haliday. 



Aphidms {Trionyx) deltigcr, Hal, I. c, $ $ . 



Toxares deltigcr, Marsh., lib. cit., p. 546, ^ $ , 

 pi. xvii, f. 7. 



$ Head and thorax black, shining ; abdomen either testaceous, 

 infuscated on the sides, or entirely fuscous ; the 1st segment 

 always rufescent. Mouth and palpi yellowish. Antenuai about 19- 

 Jointed, longer than the body, blackish with the 5 or 6 basal joints, or 

 only the 3rd joint, testaceous. Metathorax carinated in the middle, 

 and divided into regular compartments, like that of Aphidius, Wings 

 hyaline ; squamulse and radicles dull testaceous ; stigma brownish 

 yellow, nearly of the same form as that of Ephedrus calidus. Legs 

 iiifotestaceous. Abdomen of the same colour, more or less darkened 

 at the sides and posteriorly. Valves of the terebra rufotestaceous. ^ 

 Similar ; antennae 21-22-jointed, the two basal joints fuscous, the 3rd 

 testaceous (in my specimen) ; abdomen less rounded than that of 

 the 9 ; 1st segment more clearly rufous. Length, 1^ ; exp. 2i 

 lines. 



Rare in England, and unnoticed elsewhere. I have 

 never possessed more than a single example. 



IV. MONOCTONUS, Haliday. 



Hal, Ent. Mag., i, 487 (1833). 



Head transverse, rounded. Maxillary palpi 4-jointed ; labial 

 very short, 2-jointed. Antenna) not lunger than the body, with a 

 variable number of joints, greater in the ^. Mesonotum glabrous, 

 the furrows obsolete or very indistinct ; metathorax without a medial 

 carina, not areated. Prajdiscoidal areolet confounded with the 1st 

 cubital ; 2 cubital areolets at most, the 1st large, irregular, shorter 

 than in the genu.s' Aphidius, not so long as the stigma, half obsolete ; 

 stigma narrow, triangular, elongate, emitting the radial nervure from 

 its middle ; 1st abscissa of this nervure straight, placed obliquely ; 

 2nd as long as the 1st, then suddenly disappearing ; podiscoidal 

 areolet open on the inner side ; anal nervure interstitial. This 



