XXII INTRODUCTION. 



Prescutellar, a transverse row of bristles in front of the 

 scutellum. 



THORACIC PLEURAL BRISTLES. 



Propleural, bristles inserted immediately above the front 

 coxae. 



Mesopleural, bristles inserted on the mesopleuree, in the 

 angle formed by the dorso-pleural and mesopleural sutures. 



Sternopleural, one or several bristles situated on the sterno- 

 pleura, below the sternopleural suture. 



Pteropleural, bristles inserted on the pteropleurae, rarely 

 present and difficult to distinguish. 



Metapleural, bristles inserted on the metapleurae, especially 

 conspicuous in the Asilidse, and named by Lynch the 



Trichostical bristles, a fan-like row on the metapleurae, con- 

 spicuous in some families. 



Hypopleural bristles, a row or tuft of bristles on the hypo- 

 pleura, occurring in the Calyptratae. 



ABDOMINAL BRISTLES. 



Marginal bristles, bristles inserted on the posterior margin 

 of the segments, especially conspicuous in many Tachinidae. 



Discal bristles, bristles, usually one or more pairs, inserted 

 on the middle of the segments before the hind margin. 



Lateral bristles, one or more bristles situated on or near 

 the lateral margins of the segments. 



In addition, a number of terms are used to designate the 

 inclination of the bristles, often important in describing the 

 cephalic bristles. The more important of these are erect, when 

 standing vertically, or nearly so; proclinate, when directed 

 forward ; reclinate, when directed backward ; divaricate or 

 divergent when directed outward from the middle line ; con- 

 vergent when directed inwardly ; decussate or cruciate when 

 crossing each other. 



