HYMENOPTERA 335 



NN. No closed marginal cell (2d Ri + R 2 ) but the 

 basal part of the marginal vein (vein C) often present 



in the fore wings Ceraphronida and Belytidce 



MM. Fore wings without a distinct stigma. 



N. Costal cell (C + ScO either closed along the margin 

 or if open very narrow; the marginal cell (2d R t 

 + R 2 ) if present narrowly triangular, its proximal 

 margin a straight line: Abdomen not compressed 

 nor dorsally keeled. Hypopygium of the female 

 not divided, but closely applied to the pygidium, the 

 ovipositor issuing from between them at the tip of 

 the abdomen. 



Belytidce, Scelionidce and Ceraphronidce 



NN. Costal cell (C + ScO open along the costal margin 

 and abnormally wide. The marginal cell (2d Ri + 

 R 2 ) present; often closed; often open along the 

 costal margin, sometimes at tip; it is always four- 

 sided, acute at apex and at its base. Abdomen 

 more or less strongly compressed and with a mid- 

 dorsal keel, if rarely but little compressed and 

 without a keel, it is more or less swollen dorsally. 

 Hypopygium of the female divided, the ovipositor 

 issuing from the cleft thus formed, anterior to the 



apex of the abdomen, p. 349 Cynipid^; 



HH. The pronotum not reaching the tegulae, separated therefrom 

 by a chitinized sclerite, the prepectus. Antennae elbowed, never 

 more than thirteen-segmented. Fore wings with a short narrow 

 costal cell open along its anterior margin (Fig. 598); its apex 

 remote from the stigmal vein (Fig. 598, d); a more or less elon- 

 gate marginal vein (Fig. 598, b); postmarginal and a stigmal 

 spur (Fig. 598, d). An occasional trace of the transverse part of 

 vein M is the only additional vein present, there being never 



any closed cells, p. 352 Chalcidid^e 



GG. Wings longitudinally plaited in repose, ovipositor carried along 

 the mid-dorsal line. Pronotum reaching the tegulae, the prepectus 



not being distinctly set off. {Leucospis.) p. 352 Chalcidid^e 



CC. An erect scale or one or two nodes between the propodeum and the gaster. 



p. 357 Formicid^e 



BB. Hind wings with an anal lobe.* If there are any closed cells in the hind 

 wings the antenna? are thirteen-segmented in the male, twelve- in the fe- 

 male, except in a few instances where the number is reduced by fusion, but 

 then the apical segments always form a club, or are abruptly recurved or 

 otherwise strikingly modified, (except that in some species of Crabro both 

 sexes have twelve-segmented, otherwise normal antennas). 

 C. Hind wings without closed cells. Antennal segments never thirteen in the 

 male and twelve in the female, nor are the apical segments in the male 

 formed into a distinct club or otherwise peculiarly modified. Venation re- 

 duced. 



D. Abdomen attached to the dorsal surface of the propodeum Evaniidce 



DD. Abdomen attached normally, at the apex of the propodeum between 



or slightly above the hind coxas. 



E. Antennae composed of ten segments, or if of thirteen in the female 



(Ampulicomorpha) then the pronotum is elongate and has a median 



longitudinal sulcus. Antennae inserted close to the clypeus. Fore 



tarsi of the female usually chelate, p. 370. .Embolemidce and Dryinid^ 



EE. Antennae usually composed of thirteen segments, more rarely of twelve 



or eleven segments, or multiarticulate. 



F. Abdomen with six exposed segments or less. Fore wings always with 



* If there is a very deep or slit-like incision on the margin of the hind wing, the 

 insect is certain to come under this heading. There are some genera of Sphecidae 

 in which the axillary excision or both axillary and preaxillary excisions are reduced to 

 small and inconspicuous notches, close to one another, and in some cases the axillary 

 excision is altogether lacking. But in all such cases the second anal furrow is distinct. 

 In all insects falling under grouping B this furrow is wanting. 



