NO. 12 FLYING APPARATUS OF BLOW-FLY — RITTER 1 5 



transverse (di). Between Ibm and lam are found the folds Ilani 

 (division vein), Ibm and Illani. 



I lap, the anal vein (same figs.), does not arise from the knee of 

 the wing-, as is shown by Lowne in his illustration (1890-1895, v. I, 

 pi. ID, fig. i), but reaches as far as the tau of Lowne, that is, the 

 inner marginal vein of the lobulus (/. c, pi. 9, fig. 25; pi. ii, fig. 

 29, ie). It articulates with a branch of this vein by a protuberance 

 at its base. This arrangement acts as a stop that prevents the anal 

 portion of the wing from flapping too far downward. The anal 

 vein is connected with the knee only by means of a band of chitin 

 which, however, is not visble from above because it is covered by 

 the knee of the wing. The anal vein is connected with the Ilhm by 

 the transverse anal vein {aq). Between the two last-named longi- 

 tudinal veins lie the folds : Illhm, lap, the anonyma, the boundary 

 between the area media and the area postica, and Ihp. 



Ilbp, the axillary vein (same figs.), is very feeble; it can just be 

 made out as a vein. It arises at the tip of the inner marginal vein 

 of the lobulus, with which it forms an acute angle. The last fold 

 is Illap. 



The longitudinal and transverse veins divide the wing into the 

 following fields (Lowne, 1890- 1895) : 



The regio mediastinalis between gi and laa} 



The regio subcostalis between laa and Iba. 



The regio marginalis between Iba and Ilaa. 



The regio cubitalis between Ilaa and Illba. 



The regio praepatagialis between Illba and lam, proximal. 



The regio subapicalis between Illba and lam, distal. 



The regio apicalis between qi and terminal border, distal. 



The regio anterior basalis between lam and Ilbm, proximal. 



The regio discoidalis between lam and Ilbm, distal. 



The regio posterior basalis between Ilbm and Ilap, proximal. 



The regio patagialis between Ilbm and Ilap, distal. 



At the posterior border of the wing, in the regiones subapicalis, 

 apicalis, discoidalis and patagialis there are found numerous small 

 transverse folds, which extend toward the posterior border. 



All the veins taken together appear as a net or framework com- 

 posed of tubes, the meshes of which are occupied by the double 

 hairy lamella that forms the wing plate. The lamella of the wing 

 has a certain firmness. This prevents the posterior part, which is 

 not supported by any veins, from collapsing. 



'■I use the term regio instead of area (Lowne) in order to avoid a confusion 

 with the terms area antica, media, etc. 



