INTRODUCTION. XXI 



behind the upper and inner corner of the eye, erect, or the 

 inner pair convergent, the outer pair divergent. 



Post-vertical, in the middle of the upper part of the occiput, 

 generally small or absent. 



Ocellar, situated close to the ocelli, usually directed for- 

 ward ; often absent. 



Fronto-orbital bristles, placed on each side of the front, near 

 the orbit, immediately below the vertical bristles. There 

 may be one, two or none on each side. 



Loiver fronto-orbital, situated on the lower part of the front, 

 above the antennae, along the orbit, and not quite in line with 

 the fronto-orbital bristles. They are not of frequent occur- 

 rence. 



Vibrissa, a stout bristle situated near the oral margin on 

 each side. Of important use in the classification of the 

 Acalyptratae. 



Facial, a series of bristles on either side of the middle por- 

 tion of the face, above the vibrissa?, especially conspicuous 

 among many genera of the Tachinida% but usually absent in 

 the Acalyptratse. 



Thoracic Dorsal Buistlks. 



Himieral, one or more bristles inserted on tlie humeral 

 callus. 



^' Fost-hinncrnl, usually two, insei'ted immediately above the 

 dorso-pleural suture, between the humeral callus and the root 

 of the wing, on the bottom of the ])re-sutural depression. 



Pre-sutural, one or more bristles situated immediately in 

 front of the transverse suture, above the jjre-sutural depression. 



Siipra-alar, usually three bristles, one on the post-alar cal- 

 lus, one on the alar frenum and the third in front of the second 

 on the edge of the sujjra-alar de])ression. 



Intra-alar, a row of two or three bristles between the suj)ra- 

 alar group and the dorso-central bristles. 



Dorso-ccntrah two or four longitudin;d rows on the inner 

 ])art of tlie dorsum, soinctiines re])resent by tlu' 



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