22 K&y to Families of North American Insects. 



24. Basal joint of hind tarsi twice as long as the others united, the second with a 



long, spined process externally; abdomen greatly compressed, curved like a 

 pruning knife, much longer then the remainder of the body. (Ibalia.) 



IBALIIDiE 

 Basal joint of hind tarsi much shorter; second joint simple. (Andricus, Hoi- ^/ 

 caspis, Neuroterus, Synergus) (Pi. 3, 6g. 46) CYNIPEDjE 



25. Antennre distinctly elbowed (PI. 4, figs. 69, 70, 71). A few genera distributed 



among the families of Chalcidoidea. (See couplet 30.) 

 Antennre not elbowed (PI 5, fig. 85) 26 



26. Mandibles in a reversed position, the tips extending laterally and not meeting 



when closed (see couplet 18.) A few ALYSIIDiE 



Mandibles attached normally 27 



27. Abdominal petiole expanded apically, not cylindrical (PI. 5, fig. 85.) 28 



Abdominal petiole cylindrical (see couplet 22.) A few CYNIPOIDEA 



28. Ventral abdominal segments soft, with a median fold 29 



Ventral segments hard, without a fold. (See No. 19.) MYERSIID.^, part 



29. All dorsal abdominal segments free. (See couplet 20.) 



A few ICHNEUMONID.^ 

 Second and third dorsal segments usually immovably grown together. (See y 

 couplet 21.) ] A few BRACONID^ ^ 



30. Hind wings exceedingly narrow, linear, the base forming a long stalk; oviposi- 



tor issuing barely before the tip of the abdomen; antennae with the scape 

 not elongated, compressed, and without ring joint; very minute sjjecies 



with long wing-fringe. (Polynema, Gonatocerus.) MYMARED.^ 



Hind wings never very narrow, not linear or pedunculate at the base; ovipositor 

 issuing decidedly before the tip of the abdomen; antennte elbowed (PI. 4, 

 figs. 69, 70, 71), with long scape and usually with from one to three ring 

 joints • 31 



31. Tarsi five-jointed (rarely four-jointed or less in certain wingless males); axillae 



with their anterior margin usually straight and not produced anterior to the 



tegulae (PI. 4, fig. 68); spur of front tibia strong 32 



Tarsi three- or four-jointed (five-jointed or heteromerous only in the females of 

 one or two genera) ; axilla? produced forward, their front margin opposite or 

 anterior to the tegulse (PI. 4, fig. 73); spur of front tibia usually weak. . . .42 



32. Head of female long, oblong, with a deep longitudinal groove above; front and 



hind legs very stout, middle ones very slender or aborted; males wingless 

 with short three- to nine-jointed antennae. Fig insects, mainly tropical. 



(Blastophaga, Eiseniella.) AGAONIDjE 



Of a different conformation 33 



33. Mesopleura with an oblique femoral groove or impression; spur of middle tibia 



not enlarged 34 



Mesoplem-a entire, always without femoral groove in the female and usually in 

 the male; spur of middle tibia usually very large and stout. (Eupelmus, 

 Anastatus, Encyrtus, Ageniaspis) (incJuding EUPELMID.E). 



ENCYRTID.^ 



