162 SCHOOL ENTOMOLOGY 



BB. Without the knot-like structure on the petiole. 



C. First segment of the posterior tarsi hairy and adapted 

 for carrying pollen. Bodies frequently hairy and 

 rather stout. Bees. Apoidea. 



CC. First segment of posterior tarsi not adapted for car- 

 rying pollen. Usually naked forms or with few 

 hairs. (Exceptions are not rare.) 

 D. With the fore wings having a single longitudinal 

 fold or pleat when at rest. True Wasps. Ves- 

 poidea. 



DD. Front wings not folded when at rest. Digger- 

 wasps. Sphecoidea. 



