Wasps, Bees, and Ants 463 



KEY TO GROUPS OF HYMENOPTERA. 



A. Trochanters (segment between the rounded basal coxa and the long femur) of 

 the hind legs divided in two, i.e., two-segmented; female with a saw or borer at 

 tip of body for depositing the eggs. 

 B. Abdomen joined broadly to the thorax. 



C. Tibiae of fore legs with two apical spurs; female with a pair of saw-like 

 egg-depositing processes at tip of abdomen. 



(Saw-flies.) Family TENTHREDINID.E (p. 464). 

 CC. Tibiae of fore legs with one apical spur; female with elongate borer 



instead of saw (Horn-tails.) Family SIRICID^E (p. 466). 



BB. Base of abdomen constricted, so that it joins the thorax as if by a stem. 

 C. Abdomen joined to the dorsum of the metathorax. 



(Ensign-flies.) Family EVANIID..E. 

 CC. Abdomen joined to posterior aspect of metathorax. 



D. Fore wings with few veins and no closed cells (a few exceptions); 

 very small parasitic Hymenoptera. 



Families CHALCIDHXE and PROCTOTRYPID^E (p. 476). 

 DD. Fore wings with one or more closed cells (a few exceptions). 

 E. Fore wings without a stigma (Fig. 655). 



(Gall-flies.) Family CYNIPID.E (p. 467). 



EE. Fore wings with a stigma (Fig. 671); parasitic Hymenop- 

 tera, from very small to large. 



(The Ichneumons and other parasites.) Families BRACO- 

 NHXE, STEPHANID^E, ICHNEUMONID.E, and TRIGONALID.E (p. 476). 



AA. Trochanters of hind legs not divided, i.e., consisting of a single segment; female 

 often with a sting. 

 B. Fore wings with no closed submarginal cells (Fig. 683). 



C. Abdomen long and slender, and antennae also long and filiform. 



Family PELECINID^E (p. 484). 

 CC. Abdomen short, but little longer than head and thorax; antennae short 



and elbowed (Cuckoo-flies.) Family CHRYSIDID^E (p. 498). 



BB. Fore wings with at least one closed submarginal cell. 



C. First abdominal segment and sometimes the second segment in the shape of 

 a small disk-like piece (Fig. 743). 



(Ants.) Superfamily FORMICINA (p. 533). 



CC. Basal segment (or segments) of abdomen normal or elongated to form 

 a peduncle. 



D. First segment of tarsus of hind legs cylindrical and naked or with 

 but little hair. 

 E. Wings not folded longitudinally when at rest. 



(Digger-wasps.) Superfamily SPHECINA (p. 490). 

 EE. Wings folded longitudinally when at rest. 



(True wasps.) Superfamily VESPINA (p. 503). 



DD. First segment of tarsus of hind legs expanded and flattened and 

 furnished with numerous hairs, some rather long. 



(Bees.) Superfamily APINA (p 510). 



According to Ashmead our foremost American student of the classification 

 of Hymenoptera, the above table gives in some respects false indications of 



