SuB-FAMILY 
TRY PHONINAE. 
The peculiarity of the present subfamily is its almost entire restriction 
to the palaearctic and nearctic regions, on account of the scarcity of 
Tenthredinidae in the warmer and southern countries. This more espec- 
ially applies to the Tryphonides proper, for the Exochides and Metopiides 
are in no way connected therewith in Nature and are gronped under the 
common head because they share with them the characters of more or 
less sessile abdomen and concealed terebra. These two Tribes are 
really Subfamilies of equal dignity with the rest of the Tryphoninae, 
under which the Bassides and “Tryphonides can alone be truly placed, 
and they differ from each other so little as to be scarcely divisible till the 
mandibular structure be examined. To the Pimplinae none are at all 
closely allied, unless it be in the rugulose body of Metopius or the trans- 
impressed segments of Bassus; to the Ophioninae, on the other hand, 
both the Exochides and Ctenopelmini appear to lead up so naturally that 
it is difficult to tell which should be placed next them, and I have given 
the preference to the latter as being of lower specialisation. 
A Table of Tribes. 
(2). 1. Scutellum quadrate, its apical angles 
produced; face scutiform METOPIIDES. 
(1). 2. Scutellum simply triangular; face not 
centrally concave. 
(4). 3. Face very strongly protuberant, with 
frons apically concave .. EXOCHIDES. 
(3). 4. Face not protuberant, frons simply 
deplanate or convex. 
(6). 5. Mandibles with three apical teeth .. BASSIDES. 
(5). 6. Mandibles withthe i rg Sine 
not bifid .. TRYPHONIDES. 
The first two of these tribes are very highly specialised and distinct 
from the remainder, both in their structure, which is entirely peculiar 
among Ichneumonidae, and in their hosts, which alone in the present 
subfamily are sought among the Lepidoptera, in the former usually the 
Bombycidae and in the latter mainly the Tortricidae. The Bassides 
appear true Tryphoninae with peculiar mandibular modification, which it 
is very difficult to associate with the functions of a Dipterous diet, for 
they are proved to prey detrimentally upon the Syrphidae, so beneficial 
in the destruction of Aphididae. All these with the Cteniscini, are easy 
of recognition, but the remainder of the Tryphonides possess such 
indefinite generic characters, by no means simplified by the modern 
thirst for generic multiplication, that it has cost considerable labour to 
distinguish them in Nature, since their features are homogenous to a 
bewildering degree and the distinctions often minute. 
B 
