MESONOTAL BRISTLES. 



47 



of the face, above the vibrissa, especially conspicuous 

 among many genera of the Tachinidae, but usually ab- 

 sent in the Acalypterse. 



Lateral facial, one or two bristles sometimes present on 

 the sides of the face below, toward the eye. 



Postorbital, a line of small bristles nearly parallel with 

 the posterior margin of the eye, on the edge of the occiput. 



Mesonotal bristles. 



Humeral (hm), one or 

 more bristles inserted on 

 the humeral callus. 



Posthumeral (ph), one or 

 more bristles situated on 

 the inner margin of the 

 humeral callosity. 



Notopleural ( ' npl ') , usual- 

 ly two, inserted immedi- 

 ately above the dorsopleu- 

 ral suture, between the 

 humeral callus and the 

 root of the wing, on the 

 bottom of the presutural 

 depression. 



Prcsutural (pr), one or more bristles situated immedi- 

 ately in front of the transverse suture, above the presu- 

 tural depression. 



Supraalar fsaj, usually one to three bristles above the 

 root of the wings, between the notopleural and postalar 

 bristles. 



Intraalar fia), sl row or two or three bristles between 

 the supraalar group and the dorsocentral bristles. 



Postala) {pa), bristles on the postalar callus, back of 

 the supraalar. 



Dorsocentral (dc), a row on the inner part of the dorsum, 

 at the outer side of the acrostichal. 



Acrostichal {a), a. row next to the median line, on the 

 inner side of the dorsocentral; sometimes both the dorso- 



Fig. 22. Mesonotal bristles. 



