FIELD BOOK OF INSECTS. 



and entertainingly of The Instincts and Habits of the Solitary 

 Wasps, as the Sphecoidea are called. 



1. Inner margins of the eyes notched, eyes being kidney- 

 shaped; one (rarely 2) distinct submarginal cells; marginal 

 oell without an appendix; each middle tibia with a single 

 apical spur TRYPOXYLONID.E (p. 436). 



Inner margins of eyes not notched; when these are 

 slightly indented, note 3 submarginal cells 2. 



2. One submarginal cell; marginal cell with an appendix; 

 one, or no, apical spur on middle tibiae 3. 



Two or 3 submarginal cells 4. 



3. First submarginal cell separated from the first dis- 

 coidal; scutellum and post-scutellum without spines or 

 scales; eyes divergent above CRABRONID.E (p. 434). 



First submarginal and first cubital cells confluent; 

 sides of scutellum with marginal lamellae; postscutellum 

 with a spine or forked process; eyes not divergent above. 



OXYBELID^: (p. 434). 



4. Abdomen more or less constricted between the first 

 and second segments; three submarginal cells; marginal 

 cell without an appendix. PHILANTHID/E (p. 435). The 

 rare MELLINID./E may be distinguished from them by having 

 two apical spurs on each middle tibia, no recurrent nervure 

 going to the second submarginal cell, and eyes never in- 

 dented on the inner margins. 



Abdomen not constricted between the first and 

 second segments, but the first often shaped like a slender 

 petiole 5- 



5. Main part of the abdomen joined to the thorax by a 

 more or less distinct, slender petiole, which may be short 

 or long, cylindrical or flattened above 6. 



Main part of the abdomen directly joined to the 

 thorax (although there is a deep constriction between 

 them) ; 3 (rarely 2) submarginal cells 8. 



6. Middle tibiae with one apical spur; 2 or 3 submarginal 

 cells; hind wings usually with two indentations in the 

 basal half of the hind margin; small, black species 



PSENID/E (p. 434). 

 Middle tibiae with two apical spurs 7- 



7. Me so sternum produced into a forked process posteri- 

 orly ; pronotum conically produced in front ; 2 submarginal 



432 



