488 NORTH AMERICAN DIPTERA 



Metanotum — The dorsum of the metathorax, lying behind the scutellum. ( '^Ac- 

 cording to recent morphological usage this is the postnotum or post- 

 scutellum and is part of the mesonotum: the true metanotum is found 

 only in the lower Diptera, as Psychodidse.) See footnote, p. 487. 



Metapleura — The part of the metathorax above the hypopleura and outside of 

 the metanotum. It is a poorly defined area and not really separable from 

 the metanotum. 



Metasternum — The under side of the metathorax, situated behind the middle 

 coxas and extending to behind the posterior coxae. 



Metatarsus (si) — A term applied to the basal segment of the tarsi. 



Metathorax — The third segment of the thorax. The posterior legs and hal- 

 teres arise from this segment. 



Micropterous — With small or vestigial wings. 



Microtrichia — The smaller abundant hairs of the wing. When these are 

 present the wing is said to be villous. 



Moniliform — Resembling a string of beads. 



Neuration — The arrangement of the veins of the wing. 



Node — A swelling or knot-like knob. 



Notopleura — A depression, more or less triangular, situated immediately be- 

 fore the transverse suture and behind the humeri. 



Notopleural suture — The suture extending from the humeri to the base of the 

 wungs. 



Notum — The dorsal surface; particularly of the thorax. 



Ocellar bristles — Bristles arising within the ocellar triangle or on either side 

 of tlie anterior ocellus. 



Ocellar triangle — The triangle formed by the ocelli or the triangular, well 

 marked area surrounding them. This triangle has sometimes been termed 

 the frontal triangle in cases where it extends almost to the antennal base. 



Ocellar tubercle — A term applied to the swelling on which the ocelli are some- 

 times situated, especially in the Asilidae. 



Ocelli — The simple eyes, located on the front, usually near the vertex. 



Occipital cilia — The row of bristly hairs behind the eyes. 



Occipital fringe — The fringe of fine hairs behind the eyes. 



Occiput — The back of the head. Morphologically the subtriangular area limited 

 by the vertex between the eyes and the neck. 



Onychium (ia) — A pad between the tarsal claws. 



Orbit — The part of the head immediately surrounding the eyes. 



Orbital bristles — Bristles, usually proclinate or divergent, situated on the para- 

 frontals between the frontals and orbits. 



Ordinary crossvein — Anterior or small crossvein, r-m (Schiner). 



Ovipositor — The female genitalia with the adjacent parts, composed of several 

 segments and usually telescopic, but often variously modified. 



Palpi — The maxillary palpi. 



Parafacials, parafacialia — The part of the face between the facial ridges and 

 the eyes. 



Parafrontals — The part of the front outside the frontal bristles. 



Pectinate — With branches like a comb. 



Pectus — The under side of the thorax. 



Pendulous— Hanging from one end. 



Peristoma — Correctly, the region surrounding the mouth, but used in various 

 senses. The part of the cheeks nearest the oral opening. The anterior 

 oral opening. The anterior part of the cheeks. The term should be 

 avoided as being too confusing. 



Petiolate— Attached by a stalk or stem. 



Phytophagous — Feeding on plants. 



