12 BRITISH ICHNEUMONS. [ Exochint 

TRIBE 
EXOCHIDES. 
This extremely interesting and distinct tribe is at once known from the 
whole remaining Ichneumonidae by the strongly protuberant face, the 
side view of which is amazingly similar to that of a rhinoceros, and the 
very stout legs. Besides the standard works of Gravenhorst and Holm- 
gren, we have capital monographs of the Exochini by Holmgren in the 
Ofv. of 1873 and by Thomson in the Deut. Ent. Zeit. 1887; but the 
Orthocentrini is one of the least worked groups of the Ichneumonidae, 
on account of the small size and extreme similarity of its species, and 
Gravenhorst knew practically nothing of it, though Holmgren described 
some fifty species in 1855 and was ably, though somewhat too concisely, 
supplemented by Thomson in the last fasc. of his Opusc. Ent. I have 
found but little difficulty, though immense and close labour, in working 
out our indigenous species of this tribe, which numbered only thirty-seven 
at the time of the appearance of our last British catalogue, but has now 
risen to seventy-five indigenous kinds. 
The Orthocentrini have been: raised to a tribe of equal dignity with the 
Exochides, but they are so undeniably closely allied that this is, I think, 
incorrect. ‘They, moreover, provide an entirely natural link between the 
Tryphoninae and Ophioninae, since in many respects they are even more 
closely allied to the Plectiscides than to the Exochini, and care must be 
exercised not to confuse members of the former with them. 
Table of Sub-tribes. 
(2). 1. Scape not cylindrical; femora sub- 
globose; 1st seg. often shining .. nee ., EXOCHINI. 
(1). 2. Scape cylindrical; femora simply 
stout; Ist seg. always scabrous .. J8 .. ORTHOCENTRINI. 
| 
SUB-TRIBE 
EXOCHINI. 
Table of Genera. 
2). 1. Metanotum with no carinae; abdomen 
mainly flavous of PY Ae 
1). 2. Metanotum with strong carinae; ab- 
domen not mainly pale. 
. Abdomen scabriculously punctate, 
dull; 2nd seg. carinate .. .. CHORINAEUS, Holmgr. 
. Abdomen nitidulous and subglabrous ; 
2nd seg. not carinate, 
. Notauli entire to disc; basal segment 
not glabrous, 
7). 6. Antennae long and complex; meta- 
notum and petiole rugulose .. HYPERACMUS, Hlolmgr. 
(6). 7. Antennae short and simple; meta- 
notum and petiole smooth .. MICROLEPTES, Grav. 
COLPOTROCHIA, Holmer. 
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