28 Clarence E. Mickel 
5. Abdomen with a strong constriction between first and second ventral 
SOEQMENES iss ws cuss wee eee See a ee ae Woy bien oe ae 6 
Abdomen without a constriction between first and second ventral seg- 
TRGIVES 5 Bit ais ot Coie a etc calh ci ead cos teape ta eco a tee eae 8 
6. Clypeus with a lobe at dorsal middle; antennae inserted well above 
clypeus near middle of face; intermediate tibiae with two apical 
SPULS io ae hisce ee eee cei cee eotee eens eno aT ee PHILANTHINAE 
Clypeus with dorsal margin nearly straight; antennae inserted very 
close to dorsal margin of clypeus, much below middle of face.. 7 
7. Inner margins of eyes deeply emarginate; intermediate tibiae with one 
ADICAl SSM tay tate weet eR aa Eee TRYPOXYLONINAE 
Eyes at most reniform, mesal margins subparallel; intermediate tibiae 
WHI EWO apleat (SPUtS ona tase faa b.c cee eetaee ioe Cee MELLININAE 
8. Intermediate coxae without a transverse suture near base; propodeum 
long, with spiracles well removed from base; abdomen with a long 
petiole; intermediate tibiae with two apical spurs ...... SPHECINAE 
Intermediate coxae with a transverse suture near base; propodeum 
shorter, and with spiracles close to metanotum; abdomen usually 
sessile, but,when petiolate, intermediate tibiae have only one spur.. 9 
9. Metasternum with a large process which is deeply emarginate ven- 
trally; intermediate tibiae with one apical spur; wings with three 
cubital cells; radial cell with an appendage .............. LARRINAE 
Metasternum without a large, deeply emarginate process ......... 10 
10. Abdomen depressed, dorsal surface flattened; intermediate tibiae with 
two apical spurs; radial cell truncate; wings with three cubital cells, 
ASTATINAE 
Abdomen cylindrical or in a very few cases subdepressed, dorsal sur- 
face convex; intermediate tibiae with one apical spur; venation 
VAT UGUS 9 sin deosoiaces cara Maa eres Dee ees mare Ae ex ot est PEMPHREDONINAE 
NYSSONINAE 
KEY TO THE TRIBES 
1. Mesepisternum without a dorsal plate; lateral dorsal angles of propo- 
deum dentate or sharply angulate; second cubital cell petiolate, 
Nyssonini 
Mesepisternum with a dorsal and ventral plate; propodeum not den- 
EATS Pitre ota octane staun esenecstey oeler ps toke|wxalloraveralehecenp oie cveia lane Pore veiteneh tence ete nene 2 
2. Second pleural suture strongly angulate, mesepimeron therefore much 
broader above; pronotum long, cephalo-caudal length approximating 
same length of scutellum; slender insects; second cubital cell petio- 
Chea att SRA Se AT Ai RA RLS Sti Com Macon mde nir toa AY c Alysonini 
Second pleural suture straight or nearly so, mesepimeron therefore 
nearly parallel-sided; pronotum transverse; stout species; second 
cubitalcell Sessileti ee Ae somite ae eae Mee eee oe 3 
