314 THE CANADIAN ENTOMOLOGIST. 



silvery-white ; the j)arafrontals converge rapidly from the vertex, 

 meeting at the line separating the posterior and anterior halves of 

 the front, the trianguUr frontal vitta apparently ending acutely at 

 that point, continued to the base of the antennae as a scarcely per- 

 ceptible median line separating the parafrontals, which almost fusing 

 along this line form a median carina on the anterior half of the front ; 

 parafacials and cheeks silvery ; the rows of cruciate frontal bristles 

 interrupted across the anterior half of the front, from the apex of the 

 frontal vitta to the base of the antennte ; a row of six or seven 

 upwardly curving bristles extend from the base of the antennae to a 

 point a little below the arista ; front projecting in front of the eye a 

 distance about equal to the horizontal diameter of the latter as seen 

 from the side ; front narrowest at vertex, broadening anteriorly ; the 

 inner margin of the eye, as seen from in front, concave, more distant 

 at m-iddle than below ; legs black, sides of the abdomen not reddish- 

 tinged ; thiid abdominal segment with only two median marginal 



macrochsetse. Male 31. leucocepJiala Rossi. 



Frontal vitta dark brown, sometimes dusted with silvery pollen, but 

 diminishing only slightly in width from vertex to base of antennae, 

 parafrontals never approximated on anterior half of front to form a 

 median carina ; front flat, parafrontals widely separated from vertex 

 to base of antennae ; the rows of cruciate frontals not interrupted on 

 the anterior half of the front ; parafacials and cheeks thickly silvery- 

 white pollinose 2. 



2. Front projecting in front of eyes a distance equal to three-fourths the 

 horizontal diameter of the eye, as seen from the side ; frontal vitta 

 from one-fourth to one-third the width of the front ; frontal vitta dark 

 brown, sometimes thinly dusted with whitish pollen, at times wider 

 at vertex than on the anterior part of the front, parafacials never 

 approximated to form a median carina, the front flat ; legs black ; 

 abdomen not reddish-tinged ; third abdominal segment with only 

 two median marginal macrochasise. Female . . M. leucocepJiala Rossi. 

 Front projecting in front of eyes a distance equal to one-fourth to one- 

 third the horizontal diameter of the eye, as seen from the side ; 

 frontal vitta from one-half to three-fifths width of front ; front broadest 

 at vertex, narrowing anteriorly ; the inner margin of eye, as seen from 

 in front convex, more distinct below than at middle ; legs and sides 

 of abdomen often largely reddish j third abdominal segment with a 

 row of 6 or 7 strong marginal macrochaet^e M. lateralis Macq. 



