LEPTIDiE. 101 



opening, but always embracing the wing-tip.* Discal cell always 

 present, except in Rilarimorpha (non-Oriental) ; anterior cross- 

 vein near basal end of discal cell, always before its middle ; 

 4th longitudinal witli anterior branch forked, lower branch 

 simple ; posterior cross-vein nearly opposite anterior cross-vein ; 

 5th longitudinal forked at about its middle, the upper branch more 

 or less curved or angled at the point where it meets the posterior 

 cross-vein; 6th vein complete. Two submarginal cells, 5 posterior 

 cells ; anal cell open or closed ; alulae of moderate size, generally 

 well developed, absent in Xylophagin-S; ; alar squamae rather 

 small, thoracic squamae absent, " but the frenum distinct and 

 developing a rather broadened membrane near the angle ; " 

 halteres distinct, stem rather long. 



The whole body in Leptid2e is usually clothed with soft 

 pubescence, microscopically so on the often apparently bare legs. 

 There are no bristles of a chaetotactic nature, though a few short 

 ones or bristly hairs often occur about the thorax, wing-roots, and 

 metapleurae. 



Life-history. The metamorphoses of many European species 

 are more or less kuown.f Larva amphipneustic, with parchment- 

 like skin, generally living under bark, in moss, or earthy matter, 

 predaceous on Coleopterous larvae and other soft-wood insects, 

 though some are aquatic. Twelve-segmented, including head, 

 which is exserted though small, long, pointed, the mouth-parts 

 very small ; the three thoracic segments with strongly chitinized 

 dorsal areas, the prothoracic segment also hardened beneath ; last 

 segment with a strongly chitinized area on hinder part, with two 

 strong hooks, this area also bearing two spiracles. Abdominal 

 segments often with transverse swellings on lower surface, loco- 

 motion being effected by means of these, which take the form of 

 roughened intercalated spaces between the segments, though 

 Brauer affirms that true pseudopods exist in Aiherix. 



The perfect insects are found usually in open woods and the 

 meadow-lands in their vicinity, or in marshy and soft places, 

 being fond of resting on tree-trunks. 



With the exception of one or two JSTorth- American biting 

 species of Symplwromyia, which bite like Tabanid^e, the Lepxidje 

 are harmless to mankind.^ 



The LeptidjE are rather closely allied to both the Stbatiomyid^ 

 and the Tabanid^e, but the former are easily known by the 

 crowding of the venation on the front part of the wing (except 

 in Bering) and by the shape of the discal cell, which is always 

 small, and seldom much longer than wide (except in Xylomyia), at 



* In one or two European species of Xylophagus, the lower branch of the 

 3rd vein may in individual specimens occasionally end barely above the wing-tip. 



1" Atherix ibis, Xylophagus ater, Leptis tringaria, L. scolopacea, etc. 



| [Five species of blood-sucking Leptids have been described by White and 

 Ferguson from Australia and Tasmania, all belonging to the genus Spanio'psis, 

 White ; Tricliopalpus obscwrus, Phil., has been noted as a greedy blood-sucker in 

 Chile, and Leptis scolopacea, L., and L. strigosa, Mg., have been recorded as 

 biting man in France. — Ed.] 



