KEY TO SOLITARY WASPS. 



cells; marginal cell with an appendix; small, black species. 

 AMPULICID^E. Rare. Our only genus is Rhinopsis; it may 

 prey on roaches. 



Mesosternum not produced posteriorly; pronotum 

 not conically produced; 3 (rarely 2) submarginal cells; 

 marginal cell without an appendix; shining black or 

 marked with reddish-brown SPHECIDJE (p. 438). 



8. Labrum large, free, triangularly or semicircularly 

 elongated beyond the clypeus; marginal cell rarely with an 

 appendix; both recurrent nervures running to the second 

 submarginal cell 9. 



Labrum small, not or scarcely extending beyond 

 the clypeus 10. 



9. Middle tibiae with a single apical spur; labrum much 

 longer than wide; ocelli more or less aborted 



BEMBECID/E (p. 437). 



Middle tibiae with two apical spurs; labrum wider 

 than long. STIZID.^E. The only eastern species is Sphecius 

 speciosus (Plate XCII). It is our largest Sphecoid and, 

 because of the food with which it stocks its underground 

 burrows, it is called the Cicada-killer. 



10. Second submarginal cell petiolate or triangular; 

 marginal cell without appendix; middle tibiae with two 

 apical spurs; antennas arising well above the clypeus . . . . 1 1. 



Second submarginal cell broadly sessile, not tri- 

 angular or petiolate 12. 



11. Metathorax with the upper hind angles acute or 

 produced as short spines; 3, rarely 2, submarginal cells. 

 NYSSONID^E. Nest in sand ; Nysson our only genus. 



Metathorax with the hind angles rounded or obtuse. 

 ALYSONID.-E. Alyson our only genus. 



12. Marginal cell usually with an appendix; antennas 

 arising close to the clypeus; middle tibiae with i or 2 apical 

 spurs; hind ocelli frequently aborted. . LARRID/E (p. 436). 



Marginal cell without appendix; antennas arising 

 far above the clypeus; middle tibiae with 2 spurs; ocelli 

 normal. GORYTID/E. Gorytes, variously divided, is our 

 only genus. Its species nest in sand and provision with 

 Homoptera, especially Cercopidas. 



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