GLOSSARY. XXI 



Tibia. The second of the large conspicuous divisions of the legs, generally 



longer and thinner than the femora, and normally longer than the tarsi. 



In some families and genera one or two spurs or spines at the extreme 



tip furnish valuable characters in classification. 

 Tomentum. A vestitnre of exceedingly short, semi-erect hairs, finer and shorter 



than those known as " pile." Williston says that tomentutu can only 



correctly be used to desiginate "flattened, scale-like or stubble-like, 



more or less recumbent hairs which gradually merge into dust or 



pollen." 

 Transverse. At right angles to the longitudinal axis of the body, sucli as the 



transverse suture on the thorax ; or to the length of the wing, such as 



the " cross-Veins." When applied to the head or proboscis it means 



broader than long. 

 Transverse suture. See Suture. 

 Transverse veins See Cross-veins. 

 Trapezoidal cell. See Ehomboidal cell. 

 Trochanter. A small, generally annular joint uniting the coxa to the 



femur. 

 Tromoptera. Osten Sacken's superfamily for the NEMESTRINID.E, CYRTID.E, 



BOMBYLIID*, THEREVID.E and SCENOPIXID^E. Verrall confines it to the 



BOMBYLIIDJE and THEREVIDJE. 

 Truncate. Ending abruptly, as if cut off. 



Ungiies. The claws, two in number, affixed to the lower side of the 5th (ter- 

 minal) tarsal joint. The remaining portions of the feet consist generally 

 of the pulvilli and the empodium. 



Vena spuria. Only present in the SYRPHID.E, a family of the BRACHYCERA. 

 It runs in front of the 4th longitudinal vein and is merely a fold or 

 crease in the wing and not a true vein. It is sometimes indistinct but 

 invariably present in this family except in the genus Grajrtomyza. 



Venation. The system of the veins in the wings. The older dipterologists 

 spoke of it as the neuration, a synonymous term used in other 

 orders. 



Vcntriculutn. The true stomach in Diptera, as distinguished from the 

 diverticulum or sucking stomach. 



Vertex. The upper part of the head, lying between the upper angles of the 

 eyes, merging in front more or less abruptly into the frons (5-. v.). An 

 imaginary line between it and the back of the head (or occiput) is called 

 the vertical margin. 



Vertical margin. The marginal line between the vertex and the occiput. 



Vertical triangle. The small, often extremely small, space in holoptio flies 

 between the absolute vertex and the spot where the eyes first touch each 

 other. It bears the ocellar triangle (when such is distinct), which in 

 its turn carries the ocelli, when these latter are present, 



Verticillate. When the joints of the antennae are provided with verticels. 



Verticel, or verticil. A whorl of hairs arranged around an antennal joint in the 

 form of a circle. Two or more such whorls may be present on the same 

 joint. 



