966 



AN INTRODUCTION TO ENTOMOLOGY 



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

 (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 



pr.I. 



Fig. 1 1 82. — 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; antennas clavate. p. 967 . . Masarin^ 

 AA. Fore wings with three submarginal cells. 



B. Vein M4 + Cui of the fore wings elongate (Fig. 1183); cell M3 four-sided; 



wings not plaited, p. 967 EuPARAGiiNiE 



BB. Vein M4 + Cui of the fore wings exceedingly short (Fig. 11 89); cell M3 a 

 scalene triangle (Fig. 1189); wings longitudinally plaited when at rest. 

 C. Hind wings with an anal lobe (Fig. 1189). 



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. 968.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. 969 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. 973 Epiponin^e 



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. 974 POLISTIN.^ 



CC. Hind wings without an anal lobe, somewhat stalked (Fig. 1182); ab- 

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

 nests; tarsal claws simple; middle tibiae with two apical spurs, p. 975 

 Vespin^ 



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 



