222 WILMAM J. FOX. 



Eyes emarginate anteriorly, facetted. 



First and second abdominal segments sessile Gr. hexagona. 



First segment smaller than second, more or less nodose Gr. sci'upea. 



The female of group asopus is not known. 



1. Group grandiceps. 



Head large, wider ihan thorax, armed more or less with stout 

 spines. Scape long and slender. Eyes subovate. Mandibles long 

 and narrow tridentate, two small teeth being situated on inner edge 

 before the acute apex. First abdominal segment sessile with second. 

 No pygidial area. Thorax laterally ( 9 ) not crenulated. Wings 

 of male greatly abbreviated, not equalling the thorax in length. 



But one species of this group is known and is easily distinguished 

 by the characters given above. 



1. fliitilla graiidieeps Blake. 



MutiUa qrandice^s Blake, Tr. Am. Ent. Soc, iv. 74. % , 1872. 

 Siphserophfhalma grandiceps 'B\&ke,\h\i\, ■&\\\,ZiA^, 9 'J, , 1886. 



Texas. In general appearance this species is not unlike the agri- 

 cultural ant Atta. 



2. Group canadensis. 



Agrees closely with the preceding group, differing in the crenu- 

 lated thorax of female and shorter, heavier mandibles. The male 

 has the wings fully developed, with two submarginal cells, there 

 being no trace of a third ; the marginal cell is acuminate ; eyes 

 subi'eniform. 



So far as known the males of this group have the body entirely 

 black. 



FEMALES. 



Head more or less spined 2. 



Head not spined 4. 



2. Postero-lateral angles of head dentate, the cheeks with a spine 3. 



Postero-lateral angles of head bearing a carina, which terminates below in a 



sharp spine; abdomen from apex of segment 2 blackish. 



canadensis Blake. 



3. Head and thorax above, the former especially, covered with appressed, silvery 



pubescence ; postero-lateral angles of head sharply dentate. 



Tounieyi Fox. 



Head and thorax without appressed pubescence: postero-lateral angles of head 



acute, but not strongly dentate nephele n. sp. 



4. Greater part of abdomen ferruginous, the .silvery maculation, if present, thin, 



not very distinct 5. 



Abdomen black, except first and last segments, and the second ventral which 

 are ferruginous; silvery pubescence dense, consisting of a transverse 



