INTRODUCTORY PAPERS ON ICHNEUMONID. | 27 
Hymenoptera and which have a caterpillar-like phytophagous 
larva, comprises the sawflies, or Tenthredinide; the other 
section comprises seven tribes of mostly parasitic insects, in 
which the division between the thorax and abdomen is very 
distinct, and all have legless, entomophagous (except part of the 
Cynipide), larve. These have been tabulated as follows, by 
Latreille :— 
A. Ovipositor simple. 
a. Ovipositor partially coiled, and proceeding from 
near base of abdomen. - - - . 1. Cynipips. 
b. Ovipositor straight. 
* QOvipositor of three pieces. 
+ Antenne straight. 
{ Abdomen inserted at extremity of metathorax. 
§ Two recurrent nervures. - - 
§§ One recurrent nervure. - - - 
tt Abdomen inserted upon the back of meta- 
rN) 
. ICHNEUMONIDA. 
. BRACONID. 
iss) 
thorax. - - - - - - - 4. Evaniips. 
++ Antenne elbowed. - - - - - 5. CHALCIDIDA. 
** Qyipositor tubular. — - 6. OxyuURA. 
B. Ovipositor jointed. - . - 7. CHYSIDIDE. 
This shows the place which the true Ichneumons occupy 
amongst the parasitic Hymenoptera; the somewhat anomalous 
and rare T’rigonalys is included in the family Aulacide, which is 
a subsection of the Evaniide. ‘There are of course many other 
distinguishing characters, but the beginner will soon find it easy © 
to separate a true Ichneumon, with its long, slender, well-defined 
abdomen, its thickly-veined wings, and its mostly long exserted 
ovipositor, from a Cephus or Sirex, a Cynipid, a Braconid, a 
Chalcid, or a Proctotrupid (Oxyura). With the few apterous 
species there may be more difficulty at first. 
The eggs of Ichneumons vary greatly: many are whitish or 
pellucid, and peduncular in shape, while others are shining, 
black, and oval; in some species they are merely glued to the 
outside skins of their victims, while in others the female pierces 
the prey and deposits its egg within the victim egg, or larva, as 
the case may be. The means used and difficulties overcome in 
effecting this oviposition, in certain cases, is most interesting. 
The larve of the Ichneumonide are all internal parasites on 
other insects, hexapods of all orders, and frequently in the eggs 
