40 OKNERA OF HYMKNOITKRA. 



This Is one of the most diffieiilt ami nnsjitisfnctory faniilies to tnbu- 

 luto, Ih'cuuw tl»o chjirat'tcrx that have Ihhii made known are, in many 

 cases, so prone to vary and hi'come internie<iiate. For instanee : in 

 the h)ng established f,'enera Mem/eptuM and TnjphoH, the tbrnier is 

 chani<'terize<l ehietly hy the jxitiohite abdomen, and the hitter by the 

 sessile alnlomen, while Mvmleim, an inU-rmediate j;enus, is distin- 

 fiuished by the sub|K'tiolate or sid)sessile abdomen, the dittieulty being 

 to determine where one ends and the other iR'gins. Of course, tiiere 

 are other ditierential eharaet*'rs, sueh as the tnuisverse or bueeat« 

 head, carinate or 8nMH)th petiole, slender or robust legs, etc., but these 

 also show the same disposition to vary, so that there are t're<iuent 

 cases where, with our pnwt^nt im|X!i-fect knowledjjje of eliaracters, we 

 are at a loss to say in what genus the species should Ik* placed. This 

 difficulty, howeve '. 'jan be overcome by a careful study of a large 

 amount of material. 



Table of Subfamilies. • 



First segment of the depressed alMlomen, which is pedunoulate, l)ent or curved 



towards its iii>ex 2. 



First segineiit of tlie alidoiuen, as a rule, straight, its spiracles placed at the mid- 

 dle, or before the middle, rarely behind the middle, in which case the 



abdomen is fompressed .3. 



2. — Ovipositor hidden, or only slightly exserted ; basiil half or two-thirds of first 

 abdominal segment slender, the apex generally much exi)anded, its 

 spiracles not as closely approxiinate to each other as to the apex of the 

 segment ; base of second segnunt almost always with lateral pits or de- 

 pressions (gastrocoeli) ; areolet pentangular; mesothorax generally 

 without longitudinally impressed lines (parapsidal grooves). 



IcbneumoninBB. 

 Ovipositor distinctly exserted, rarely short as in S*ilp)ms ; spiracles of first 

 abdominal segment more approximate to ea.-u other, as a rule, than to 

 the apex of the segment, which is sometimes scarcely ex jwinded ; areolet 

 pentangular, (luadrate or incomplete; sometimes wingless or nearly so 

 as in Pesomachus and allied genera; mesothorax generally with distinct 



parapsidal grooves; ga.strocoeli subobsolete or wanting CryptinsB. 



3. — Ovipositor short or not exserted, rarely long, as in .some genera of Ophioninse. 

 Abdomen compressed throughout or only the posterior half, petiolate, 

 rarely sessile or subsessile as in Banchus; areolet triangular, rhomboido- 

 triangular, or wanting ; face generally clothed with a short, dense, se- 

 riceous pubescence Ophioninae. 



.^.bdomen sometimes completely depressed and sessile as in Metopius, liassus, 

 etc., generally not entirely depressed, largest towards the apex which is 

 often subcompressed in f , elongate, fusiform, sessile or petiolate, in the 

 latter case never with the areolet pentangular; areolet irregular, trian- 

 gular or wanting, rarely pentangular TryphonlnsB. 



•ir^^ 



