NO.120C. ICHNEUMON FLIES— ASHMEAD. 3 



a. Pronotum not extending ])aok to the tegul;e; trochanter one-jointed. 



h. Hind tarsi dilated or thickened; pubescence of head and thorax 

 feathery oi phiniose. Superfaniily I. APOIDEA. 



hh. Hind tarsi slender, not dilated or thickened; pubescence of head 

 and thorax simple, not plumose. 



Superfaniily II. SPHECOIDEA. 

 aa. Pronotum extending l)ack to the teguke, or the latter absent. 

 0. Trochanters always one jointed. 



d. Abdomen variable, rarely twice longer than the head and tho- 

 rax united, most frequently much shorter; hind tibife in 

 female neither inflated nor strongly constricted at base. 

 Petiole or first segment of abdomen simple, leithout a scale 

 or node; winged forms v:ith well developed tegute. 



Superfamily III. VESPOIDEA. 

 Petiole or first segment of abdomen with one or two scales or 

 nodes; winged forms tvithout or with very imperfectly 

 formed tegula;. Superfamily IV. FORMICOIDEA. 

 dd. Abdomen in female greatly elongated, several times longer 

 than the head and thorax united, the segments con- 

 stricted at sutures and flexible; hind tibife in female 

 inflated and strongly constricted at base; abdomen in 

 male not especially long, clavate. (Pelecinidfe.) 



Superfamily V. PROCTOTRYPOIDEA (part). 

 cc. Trochanters two-jointed. 



Mandibles large, 4-dentate; liind wings vith a distinct venation, 

 with two basal cells and a radius. ( Trisonalidfe. ) 



Superfamily III. VESPOIDEA (part) . 

 Mandil)les never very large nor 4-dentate, either simple or 

 ]>identate, or at the most 3-dentate; hind wings without a dis- 

 tinct venation, or at most and rarely with only one basal cell, 

 the radius always absent. 



Superfamily V. PROCTOTRYPOIDEA. 

 * * Hypopygium divided or never united closely with the pygidium, the ovii^osi- 

 tor issuing some distance before the tip of the abdomen; trochanters always 

 tivo-jointed. 



d. Front wings always vitlujvt a stigma, the marginal vein, if 



present, linear never large or stigmated; abdomen with 



the ventral segment hard and chitinous, without a fold. 



e. Pronotum extending back to the tegulaj; front wings 



with a marginal and basal cell, either complete or 



incomplete; antenna^ straight, not elbowed. 



Superfamily VI. CYNIPOIDEA. 

 ee. Pronotum ;(o/ extending back to the tegute; front wings 

 with neither a marginal cell nor a distinct basal cell, 

 the latter, if at all indicated, usually poorly defined liy 

 hyaline veins visible only by transmitted light; hind 

 wings without a liasal cell; antennte elbowed. 



Superfamily VII. CHALCIDOIDEA. 

 dd. Front wings vitJi a stigma, the marginal vein usually large 

 or stigmated (rarely linear in some Alysiida?); abdomen 

 with the ventral segments most frequently soft and mem- 

 branous, with a fold (rarely hard and chitinous without a 

 io[d,Evaniidpe and Agriotypida;) ; pronotum always extend- 

 ing back to the tegul.ie; antennae straight, not elbowed. 

 Superfamily VIII. ICHNEUMOXOIDEA. 



