Vol. 1] Bradley.— The Taxonomy of the Masaricl Wasps 373 



In the more primitive members of each of the major groups of 

 aculeate Hymenoptera (i.e., Formicoidea, Vespoidea, Scolioidea, Sphe- 

 coidea, and Apoidea) both axillary and preaxillary excisions are pres- 

 ent, and accordingly both posterior and preanal lobes are well devel- 

 oped. Each have been lost in some or most of the specialized members 

 of each superfamil3^ The tendency of specialization throughout the 

 aculeates has been toward a reduction of the anal area of the hind 

 wing, and especially of the posterior lobe. 



With this tendency to reduction in mind, let us turn to Euparacjla, 

 representing the Euparagiinae, and consider the wing (fig. 100). The 

 posterior lobe is large, two-thirds the length of the cell M, -|- Cu -\- CUi. 

 In all other subfamilies except the Vespinae the posterior lobe is re- 

 duced to a small round or oval flap at the extreme base of the wing, 

 from one-fifth to one-third the length of the cell M, -|- Cu + C^i^. In 

 the Vespinae the posterior lobe has been so completely reduced that it 

 is altogether wanting. In this respect, as in others, Euparagia, stands 

 out alone as ancestral, while the Vespinae take their place as most 

 specialized. 



In all cases except the Vespinae the preaxillary excision is an in- 

 significant notch, a mere undulation, or is altogether lacking. In the 

 Vespinae it is deeper. Taking the order as a whole, it would seem 

 that the primitive condition of the preaxillary excision is a distinct 

 notch, but not a deep incision. The precise condition seems subject to 

 variation within narrow:er limits than in the case of the axillary. 



In the Vespinae the anal area of the hind wing is greatly reduced, 

 so that the wing is subpetiolate. 



THE CENTRAL AEEA OF THE HIND WINGS 



The venation of the central area of the hind wings is of consider- 

 able taxonomic importance. By referring to figures 97-101 and 104, 

 plates 13, 14, 15, the modification it has undergone will be seen. 

 Figure 98 represents a primitive condition (for aculeates) in which 

 M.. is transverse, m and Mo are inserted below its middle, and the 

 caudal part of M., is interrupted just before its union with M^ -|- Cu^+o 

 -|- 1st + 2d A by a bulla. The bulla is formed by the crossing of the 

 1st anal furrow, which is present, and which is lying immediately 

 cephalad of 1st A and its amalgamates. The furrow ends in a pre- 

 axillary excision. 



