IPHIATJLAX. 355 



fuscous hair ; front depressed in the centre, the furrow rather deep. Petiole with the 

 central part of nearly equal width from the base ; the base depressed ; the apex trans- 

 verse ; the inner furrow wide, deep, twice the width of the outer one. The keel on the 

 second segment becomes gradually narrowed to the apex, and reaches nearly to the end 

 of the segment; its basal part not distinct from the rest, and there is a shallow 

 depression on either side of it ; the lateral furrow wide, curved, and reaching to the 

 apex. Suturiform articulation wide, crenulated in the centre, the lateral branches 

 smooth. The furrow on the third segment is quite close to the base, and does not 

 reach to the sides. The abdomen is a little longer than the head and thorax united, 

 and becomes somewhat sharply narrowed from the third segment ; the petiole rises 

 gradually from the base. Fore wings with the cloud at the stigma not so long as 

 the petiole, and contracted in the centre, the apical cloud commencing a little beyond 

 the third cubital nervure ; the second cubital cellule (at least on the lower side) a little 

 longer than the third ; stigma black, the nervures testaceous in the hyaline parts of the 

 wings. Hind wings light smoky-hyaline, darker at the basal half. 



b. Wings uniformly smoky. The keel on the second segment dilated at the base ; the 

 dilatation distinct, so that the keel does not become gradually narrowed to the apex. 

 (Species 38-40.) 



a. No keel on the third and fourth segments. Palpi black. Abdomen becoming 

 gradually thickened to the apex of the fourth segment, then somewhat sharply 

 narrowed to the apex ; a stout keel dividing the lateral depression on the second 

 segment in two ; the basal branch of the suturiform articulation nearly, if not 

 quite, straight, the apical branch curved and reaching to, or a little beyond, the 

 middle of the segment ; the latter with a transverse depression at its apex ; the 

 furrow on the third segment not striated, curved. (Species 38 & 39.) 



1 (2) . A Y-shaped keel on the petiole ; anterior tarsi white fuscidens. 



2 (1). No Y-shaped keel on the petiole ; anterior tarsi black .... vercepacis. 



*% 38. Iphiaulax fuscidens. (Tab. XIV. fig. 19, <? .) 



/Niger, mesonoto strigaque metanoti sordide rufis, abdomine tarsisque anticis flavo-testaceis ; alia fuscis. $ . 

 ' Long. 11 millim. 



Eab. Mexico {Salle). 



Antennee as long as the body, tapering perceptibly towards the apex ; microscopically 

 pilose; the joints clearly separated; basal joint with a short petiole, shorter than the 

 third and fourth joints united, the apex produced on the lower side. Cheeks coarsely 

 and irregularly rugose, opaque, pilose ; face smooth, shining ; front deeply excavated ; 

 a furrow (wide at the base, gradually narrowed towards the apex), margined on either 

 side, proceeding from the ocelli to the antennae. Abdomen scarcely twice the length 



2 zz 2 



