PWMILY TIPULID.K THE CRANE FLIES 35 



aria, where the free tip of vein Scg has migrated along vein R^ to occupy 

 the extreme tip of the vein. A series of diagrams (Figs. 3 to 10) indi- 

 cates this tendency, which involves many hundreds of species in the 

 vast genus Limonia. The medial and cubital fields are interpreted ac- 

 cording to the Tillyard modification of the Comstock-Needham system. 



Male hypopygium usually simple, the basistyles (coxites) bearing 

 the dististyles (styles) at or near apex. Aedeagus and its subtending 

 gonapophyses furnishing characters of paramount importance for spe- 

 cific determination. A dorsal lobe of the basistyle, the interbasc, some- 

 times present. Ovipositor with the tergal valves (cerci) lengthened, 

 heavily sclerotized, usually gently to strongly upcurved, exceeding the 

 short, straight sternal valves (hypovalva?) ; in a few cases (as some 

 TipulinjE; Cylindrotomina?; Styringomyia and others), the valves of the 

 ovipositor are short and fleshy. 



Tipulidae are great lovers of moist conditions, being chiefly re- 

 stricted by humidity. Species have been taken within 600 miles of the 

 North Pole, while others occur at altitudes of over 17,000 feet in Thibet. 

 The majority of the species occupy the intermediate zone, the familj^ 

 being very numerous in species in all temperate parts of the World 

 and similarly numerous in the subtropical and temperate portions of 

 the mountainous regions of the Tropics. Lowland tropical species are 

 fewer in luiniber and are apt to have a very wide distribution. The 

 lesser oceanic islands are practically devoid of the larger crane flies 

 (TipulinaO while having numbers of species of the small fragile Li- 

 moniina^ (as Limonia, s.l.; Stf/rinffomj/ia; Gononii/ia: Lipophleps; Tren- 

 tepohlia). ITnder rigorous conditions, as the arctic, wind-swept coasts, 

 high mountains and the like, species with reduced wings are frequently 

 found, being most numerous in the female sex. The greatest reduction 

 of wings is found in Chionea, wliich is virtually apterous in both sexes. 



The Tipulidtr of the World now include more than 6000 species, 

 arranged in 2S3 genera and subgenera (Tipulinse, 76, Cylindrotominte, 

 9; Limoniina', 198, the latter further distributed in the following tribes: 

 Lechriini, 4; Limoniini, 37; Pediciini, 12; Hexatomini, 70, and Eriop- 

 terini, 75). Representatives of all tliree sulifamilics and of all tribes 

 witli tlie exception of the Tjcchriini occur in tlie area under considera- 

 tion. 



Keys availalile for tlie idi'utification of tlie adult flies are very few 

 in number. The writer's preliminary study on the "Crane flies of New 

 York", is now seriously out-of-date due to the great additions made in 

 intervening years. The forthcoming volume on Diptera in the "In.sects 

 of Connecticut'' series will largely supercede the earlier work. Both 

 of these reports are restricted to the area embraced in northeastern 



