AMERICAN HYMENOPTERA. 93 



DKSCRIPTIOX OF A SE.\¥ GEXUS AKD OF FOUR NEW 

 SPECIES OF HYMEXOPTERA. 



BY P. CAMERON. 



ZETHOIDES gen. nov. 



J' . — x\ntenu?e clavate, the base of the flagelluni narrowed ; the 

 scape as long as the foHowing two joints united. Eyes large, con 

 verging below, the malar space almost obsolete. Clypeus about 3 

 times longer than wide, its apex rounded. Labrum hidden. Man- 

 dibles becoming gradually narrowed towards the apex. Maxillary 

 palpi with at least 4, the labial with at least 3 joints. Abdominal 

 petiole as long as the rest of the abdomen united, narrowed at the 

 apex and at the base of the 2nd segment as in Zethus ; 2nd segment 

 bell shaped, as long as the other segments united. Ventral surface 

 slightly convex. Radial cellule appendiculate, the stigma large; 

 there are 2 transverse cubital nervui-es; the cubitus extends to the 

 apex of the wings, its 2nd abscissa is the longer, the 1st the shorter; 

 the first recurrent nervure is interstitial ; the second is received at 

 the base of the apical third of the cellule. Transverse basal nerv- 

 ure interstitial. Scutellum large, flat, its apex roundly margined. 

 Median segment with a rounded slope towards the apex ; reticula 

 ted, its centre with 2 longitudinal keels. Legs slender, the middle 

 tibije with 2 spurs; the claws simple. 



I am not quite certain if the wings fold naturally in repose or 

 not. In one example they did do so after being moistened for the 

 purpose of being cleaned. The presence of 2 spurs on the middle 

 tibiae removes the genus from the Eumenidse, as do also the fact of 

 there being only 2 transverse cubital nervures, which fact also sepa 

 rates it from the Vespidse, which have 2 spurs on the middle tibiae. 

 There is no hook on the end of the antennae as in the male Eumeni- 

 d^e. The alar neuration and the clavate antennte would place it 

 with the Masaridse, but from the known species in that group it 

 maybe readily separated by the long abdominal petiole (except from 

 Paramasaris, which differs in other respects). It has very nuich the 

 form of Zethus, especially in the form of the abdomen 



The pronotum is transverse, but not acutely spined ; the eyes are 

 margined behind, as is also the occiput; there is a conical protuber- 



TRANS. AM. KNT. SOC, XXX. MARCH, 1904. 



