HYMENOPTERA 949 



tegulce; cell M4 of the fore wings is longer than cell Cu+Cui 

 (Fig. 1 182); and there are closed cells in the hind wings. 



The typical wasps found in America north of Mexico represent 

 seven subfamilies of the family Vespidas. These can be separated 



■^*c. 



Fig. 1 182. — Wings of Vespa diabolica: pr. I, preanal lobe; pr. exc, preaxillary 

 excision. (From Bradley.) 



by the following table, for which I am indebted to Professor J. C. 

 Bradley. 



A. Fore wings with two submarginal cells; antennae clavate. p. 950 . JVIasarin^e 

 AA. Fore wings with three submarginal cells. 



B. Vein M4 + Cuj of the fore wings elongate (Fig. I183); cell M3 four-sided ; 



wings not plaited, p. 950 Euparagiin^ 



BB. Vein M4 + Cui of the fore wings exceedingly short (Fig. 1 189) ; cell M, a 

 scalene triangle (Fig. 1 189); wings longitudinally plaited when at rest. 

 C. Hind wings with an anal lobe (Fig. 1 189). 



D. Tarsal claws bifid; middle tibiae with one apical spur; solitary wasps 

 without a worker caste. 



E. Mandibles short, obliquely truncate and toothed at the apex, 

 folding above each other beneath the clypeus or very slightly crossing; 

 head quadrate; abdomen petiolate, the apex of the petiole globose 

 and strongly constricted before the second segment, p. 951 . Zethin^ 

 EE. Mandibles elongate, crossing each other or placed parallel in a 

 long sharp beak ; if the abdomen is petiolate the head is transverse. 



p. 952 EUMENIN^ 



DD. Tarsal claws simple; middle tibiae with two apical spurs; social 



wasps building open or closed paper nests. 



E. Extensory muscle of the abdomen fixed on the thorax in an oval 

 slit between the apical scales of the propodeum; the slit always 

 broadly rounded at its upper angles, p. 956 Epiponin^ 



EE. Extensory muscle of the abdomen fixed on the thorax in a narrow 

 and much compressed slit between the apical scales of the propodeum. 



p. 957 POLISTIN^ 



CC. Hind wings without an anal lobe, somewhat stalked (Fig. 1 182); ab- 

 domen conical; social wasps with a worker caste, building closed paper 

 nests; tarsal claws simple; middle tibiae with two apical spurs, p. 958. 

 VeSPINvE 



If we take into account only the habits of these insects the sub- 

 families of the typical wasps can be separated into two groups, the 

 solitary Diploptera, those in which a single female makes a nest for 

 her young, and the social Diploptera or social wasps, in which many 

 individuals work together to make a nest. This grouping of the 



