IPHIAULAX. 353 



The group of I. basimacula. 



The keel on the second segment in the female broad, gradually narrowed to the apex 

 (which is not acute), reaching to the apical third of the segment, and bordered by a 

 depression ; in the male narrow, raised, dilated at the base, and not bordered by a 

 furrow. Suturiform articulation broad, bifurcating near the middle, obscurely 

 striolated at the edges, especially in the male. Body and legs black, except the 

 basal segments beneath in the female, and sometimes above in the male. Wings 

 black. (Species 35.) 



If I have correctly united the sexes, it would appear that the keel on the second 

 segment may vary in form in the sexes of the same species. 



j\ 35. Iphiaulax basimacula. (Tab. XV. figg. l, $ , 2, <? .) 



* Niger, abdominis basi sordide rufo ; alia fuliginosis. <$ 2 • 

 Long. 15-17 millim. ; terebra 13-14 millim. 



Hah. Mexico, Valladolid in Yucatan (Gaumer); Guatemala, Zapote, San Geronimo, 

 Purula (Champion); Panama (Boucard), Caldera in Chiriqui 1200 feet, Tole (Cham- 

 pion). 



Antennae stout, as long as the body, with upwards of seventy joints. Head covered 

 with blackish hair, the face obscurely punctured ; front depressed in the centre, the 

 furrow narrow; eyes oval, bordered. Metathorax (especially at the sides) sparsely 

 covered with rather long white hair. Abdomen a little longer than the head and thorax 

 united, bulging out in the middle. Petiole with the central part narrowed at the apex ; 

 the base deeply depressed ; two oblong shallow fovea? in the middle ; the inner furrow 

 moderately deep and broad, the outer furrow placed lower down on the opposite side of 

 the keel. The oblique depression on the second segment is wide and moderately deep. 

 The furrow on the third segment nearly straight, narrow, the other furrows invisible. 

 The apex of the abdomen covered with longish black hair. Legs stout, densely pilose. 

 Wings long ; the recurrent nervure not interstitial ; two small hyaline fasciae in front of 

 the latter, and one at its base behind. 



In the male the central part of the petiole is not narrowed behind, and the furrow 

 bordering it is much wider and not curved at the apex as in the female ; there is an 

 obscure keel on the third segment in the centre, and the furrow at its apex, and also 

 that at the apex of the fourth segment, is wider and deeper. The upperside of the base 

 of the abdomen is entirely black above, or the petiole and more or less of the second 

 segment may be reddish. 



biol. centb.-amee., Hymenopt., February 1887. 2 zz 





