374 University of California Publications [Entomology 



In Euparagiinae (fig. 100) this primitive condition is maintained 

 except that m has migrated cephalad along Mg to the point of separa- 

 tion of the latter from M^. The crossing of M3 by the first anal furrow 

 is represented by a bulla, and the very faintest trace of the apical 

 section of 1st A and its amalgamates is to be seen. 



The subfamilies, which have ordinarily been classed as Eumenidae 

 and Vespidae proper, are represented by figure 99. The vein M, is 

 strongly angled, receiving m and Mo at the angle. Both the latter 

 vein and the apical section of 1st A and its amalgamates are ordinarily 

 retained as fully formed veins, in some cases only as traces, but they 

 are never wholly lost. First A ends, as always, in the preaxillary 

 excision. 



The Masaridinae have been derived from the type of figure 99 by 

 the complete dropping out of the apical section of 1st A and its amal- 

 gamates. The wings of this subfamily are represented by figure 101, 

 and what has happened to them is diagrammatically shown in figure 

 104. In the latter case the lost apical section of 1st A and its amal- 

 gamates and the anal furrow are represented respectively by a dotted 

 and a dashed line. 



In all of the Masaridinae the bulla indicating the crossing of M, 

 by the first anal furrow has been lost, and as the vein formed by the 

 union of Mg with M^ + Cu^+o + 1st + 2d A has straightened out it is 

 impossible to point out the exact spot where it occurs. 



The evidence for this interpretation of the hind wing of the Masa- 

 ridinae lies in the position of the preaxillary excision. It is not the 

 obvious interpretation from a casual examination of the wing, and in 

 the keys I have referred to the condition as "Mg apparently straight 

 and m lacking." 



In the Gayellinae (fig. 97) both the apical section of 1st A with its 

 amalgamates and m and Mo are fully preserved, but the vein m and 

 Mo has migrated apicad along m-cu to a point remote from Mg, a con- 

 dition not infrequent in other aculeate Hymenoptera, but not occur- 

 ring elsewhere in the Vespidae. Mg is transverse and straight, there- 

 fore primitive, as in Euparagia, while the sidewise migration of ra 

 and Mo must be considered a specialization. 



