GLOSSARY OF TERMS USED IN DIPTEROLOGY 489 



Pilose — Having long, fine hair, usually dense. The term is loosely applied 



to include any hair that is not coarse. 

 Pleurites — A term applietl to the sclerites or sections of the pleura. 

 Pleurotergite — The hypopleura; morphologically the lateral division of the 



metanotum (postscutellum), at least in Nematocera. 



PLEURAL DIVISIONS OF SYRPHUS 



Hypo, hypopleura; Meso, mesopleura; Meta, metapleura; Pro, propleura; 

 Ptero, pteropleura; Sterno, sternopleura. 



Plumose — Having rays on both sides like a feather. 



Pollen — A fine, dust-like substance on the integument. 



Pollinose — Covered with "dust" or "bloom". 



Posterior calli — The swellings at the posterior coi'ners of the mesonotum, 



present in the Calypteratae, and other families, but absent in the Acalyp- 



teratse as a rule. (Posterior callosities). 

 Posterior cells — The cells on the apical part of the wing lying between the 



third and fifth veins, exclusive of the discal cells (R.-; to Cu,). Some of 



these cells may be closed by the union of veins apically. 

 Posterior crossvein — The vein or veins closing the discal cell apically (m and 



Ms) . According to Schiner the basal section of Cui of the Comstock- 



Needham System. 

 Posterior orbits — The part of the head immediately behind the eyes. 

 Posthumeral bristle — A bristle situated behind the humerus. 

 Post ocellar(s) (bristles) — A pair (or more) of bristles arising just below the 



vertex on the occiput and behind the ocellar tubercle, sometimes termed 



post-verticals. 

 Postscutellum — A convex, transverse swelling below the scutellum; actually the 



upper, posteriorly produced section of the metanotum. 

 Postvertical(s) bristles — See post ocellars. 

 Praefurca — See prefurca. 

 Pra — Prealar bristle. 



Prasscutum — The part of the mesonotum in front of the transverse suture. 

 Pi-ealar (bristle) — The anterior supra alar bristle. This is frequently absent 



or reduced. It is used particularly in Muscidae. 

 Prefurca — The petiole of the second and third longitudinal veins. Base of 



R4.0 (The Radial sector Rs). 

 Preapical bristle (of tibia) — A dorsal, short bristle situated before the end of 



the tibia. 

 Prescutum — See prsescutum. 

 Presutural bristle — A bristle situated in front of the inner end of the noto- 



pleui-a in front of the suture. The lateral bristle situated in front of but 



close to the suture. 



