GLOSSARY OF TERMS USED IN DIPTEROLOGY 485 



Dorsal — Pertaining to the upper surface of the body. 

 Dorsocentrals — Dorsocentral bristles of the thorax. 

 Dorsopleural suture — See notopleural suture. 

 Dorsum — Upper surface. Refers to thorax and abdomen. 



Epaulet — The first "scale" at the base of the costa. It is haired and is fol- 

 lowed by a bare "scale", the basicosta. 

 Empodium (ia) — A bristle, hair or pad borne on the apical tarsal segment 



between the pulvilli. 

 Epiphysis — A lappet-like process or lobe. 

 Epistoma — Correctly, the anterior oral margin. Frequently used to denote 



the facial depression or middle of the face from the oral margin to the 



antennje. 

 Eyes — The compound eyes, composed of, usually, many facets. 

 Face — The front of the head between the mouth and the antennae. 

 Facets — The divisions comprising the compound eyes. 

 Facial depression — The middle of the face. Facial plate. 

 Facial plate — The central part of the face. 

 Femur (femora) — The long part of the leg nearest the thorax, but separated 



from the thorax by the coxa and trochanter. The thigh. 

 Fifth longitudinal vein — The vein running along the posterior side of the 



second basal cell, and of the discal cell, usually two-branched, the second 



branch separating the fourth and fifth posterior cells. (Cui,;; postical.) 

 First basal cell — A cell lying between the first, second and third and the fourth 



longitudinal veins on the basal half of the wing. 

 First vein — The vein lying immediately behind the auxiliary vein, or when that 



is absent, immediately behind the costa. (R and Ri.) 

 Flagellum- — In flies having six br more antennal segments the portion beyond 



the scape. 

 Fourth longitudinal vein — The vein, usually arising near the base of the wing, 



separating the two basal cells and bordering the discal cell anteriorly, often 



branched, the posterior branch often partly closing the discal cell. 



(Medial, M,,:, 3; discoidal.) 

 Front — The space between the eyes lying above the antennae and limited by 



the vertex or top of the head. 

 Frontalia — The central stripe of the front. Frontal vitta. 

 Frontal lunule — The space between the bases of the antennte and the ptilinal 



or frontal suture, actually occurring only in Cyclorrhaphous Hies, but the 



term, or "lunula", is loosely applied to some other flies. 

 Frontal orbits — The space contiguous to the eyes on the front. 

 Frontals or frontal bristles — Bristles situated along the inner edge of the 



parafrontals. 

 Frontal triangle — The triangle in holoptic flies bounded above by the eyes and 



below by the antennae. 

 Frontal vitta — The softer area between the rows of frontal bristles or hairs 



extending from the antenna? to the ocelli. This allows the head to expand 



laterally in Cyclorrhaphous Diptera when the ptilinum is expanded. 

 Fronto-orbital bristles — -The orbitals or orbital bristles. The term is variously 



used and is often applied to the frontals in the Acalypteratse. 

 Gena (nae) — The cheek. Often refers to the parafacials. The term is best 



avoided. 

 Geniculate — Abruptly bent or elbowed. 



Genitalia — The external sexual organs together with the adjacent parts. 

 Gibbous — Pufl'ed out; hunch-backed. 

 Glabrous — Without hairs; smooth. 

 Halteres — Appendages arising on the posterior of the pleura, with a long 



stem» and apical knob. These occur in practically all Diptera, rarely being 



