360 DIPTERA. 



The function of the halteres, or "poisers," is still problema- 

 tical. Hicks and Leyclig consider them as organs of hearing, 

 while Goureau and Loew think they are concerned in the act 

 of respiration. 



Besides the well known wingless genus Chionea, and the 

 Flea, Sheep-tick, and Braula, Loew, the eminent German ento- 

 mologist, enumerates several European species of Tipula, the 

 females of which have the wings rudimentary ; and also a spe- 

 cies of Limnobia (Idioptera). Epidapus is wingless in both 

 sexes. " Psyllonryia, Apterina and Elachiptera, and species 

 of Tachista, Chersodromia and Geomyza have rudimentary 

 wings in both sexes ; in other forms the wings are only abbre- 

 viated in. both sexes (Sciomyza), or in those of the male or fe- 

 male are smaller than in the other sex (species of Empis, 

 Rhamphomyia, Idioptera and Tipula)." 



FIG. 270. T>inf/ram of a u-iny with tu-o submarginal anil fire pouter lor ccUx ( CJadura 

 indit-isa). Cells: 1, cos(:il; "2. subcostal; :!, marginal; 3*, inner marginal; 4, snb- 

 marginal; 5, second submarginal j c-io, tivst to lil'th posterior; 1], diseal; 12, first 

 basal: 1.!, so -ond basal; 14, anal; 15, axillary; 1'i, spurious. Teiii;;: b ?, auxiliary; 

 c m, lir-t ] ingitndin;;!; li,n,o, second longitudinal; /( /, pra-i'nrca ; 7,- , anterior 

 branch of the second longitudinal vein; /.: o, posterior branch of the second longi- 

 tudinal vein; i /.:, petiole of the (irst submarginal cell: i p, tiiiril longitudinal; d q 

 r.s' t, fourth longitudinal; q r, fork of its anterior bnmvh : the ]io.-terior branch of 

 this fork, ending in /, is Mr. Loew's <nifi-ri<ir iitfereiilar// n in ; .v ,', fork of the pos- 

 terior braucli of tiie fou : I : v>.-'n : the branch of this fork, ending in t, is Mr. Loew's 

 posterior intercalary vela ; e </, fifth longitudinal; / r, sixtli longitudinal: // w, 

 seventh longitudinal. Cross-veins: x, humeral; x x, subcostal; xxx, marginal; 

 x*, small, or anterior cross-vein; x** t gi'eat cross-vein. From Oslcn Sacken. 



Fig. 270. 



FIG. 271 (1). Win ft of Orti'ilifi. a, transverse shoulder-vein; 6, auxiliary vein; c, 

 </, e, f, y and h, first, second, third, fourth, fifth and sixth longitudinal veins; i, 

 small or middle transverse vein ; /,, hinder transverse vein : I, m, , o, costal vein; 

 p, anterior basal transverse vein; t/, posterior basal transverse vein; r, rudiment 

 of the fourth trunk ; .<, a xillary incision ; A, B, and C, first, second and third costal 

 cell-; D, marginal cell: /;, submarginal cell; F, G and //, first, second and third 

 posterior cells; /, discal cell; A", first or large basal cell; L, second basal cell, or 



