414 C. R. Osten Sacken': 



anderer Stelle bei Gelegenheit zu sprechen; nur möchte ich gegenüber 

 der Aeusserung (p. 187): „It seems to me that etc.", was sich auf 

 die von mir gegebene Flügelabbildung bezieht, erklären, dass die 

 Abbildung richtig ist." 



As Prof. Mik has not made good yet his promise of further 

 explanations, and in presence of his very positive statement about 

 the correctness of his figure of the wing, I feit bound, to prevent 

 further misconceptions, to give the subject a renewed study and to 

 publish the result. This result is founded upon the comparison of 

 specimens, as well as of the descriptions. 



The principal points of difference that may be urged against the 

 identification of these two genera are found in the wings, whereas 

 the bodies are remarkably alike in structure and coloring. The 

 wording of Prof. Mik's diagnosis of Orimargula (Wiener Ent. Z. 

 1883, p. 198), as far as the body is concerned, corresponds nearly 

 word for word with my description of Antocha (Monogr. N. A. Dipt. 

 IV, p. 124). Thus Mik has: „Tibiarum apices calcaribus nullis, em- 

 podium perparvum, angustum" ; and 0. S.: „Tibiae without spurs, 

 empodia indistinct" ; Mik: „ungues ad basim furcati" ; 0. S.: „ungues 

 with small teeth on the underside, at the basis"; Mik: „antennae 

 16 articulatae" ; the same in 0. S. ; Mik: „forcipis maris articuli 

 basales coniformes, ante apicem appendiculis binis altera unguiformi, 

 altera lamelliformi"; compare with this statement the figure of the 

 forceps of Antocha, given by 0. S. 1. c. Tab. III, f. 10, and the de- 

 scription : „the forceps of the male has, on the usual basal pieces, 

 a double claw-shaped appendage, which consists of a horny and a 

 soft part, closely joined". The ovipositor of both species, as I com- 

 pare them, shows no difference. The mode of life is the same: both 

 species occur in the vicinity of, and sometimes alraost in contact 

 with water. 



In comparing my heliograph of the wing of A. 02)alizans (1. c. 

 Tab. I, f. 11) and Prof. Mik's figure of the wing of Orimargula Mik, 

 1. c, the resemblances become at once apparent: the acute angle at 

 which the second vein issues from the first is the same in both 

 (quite different in Orimarga\)\ in both, this origin is much nearer 

 to the root of the wing than in the neighbouring genera; in both, 

 the submarginal cell is considerably longer than the first posterior; 

 in both the two last longitudinal veins are straight (and not un- 

 dulating as in Orimarga). In the figures there is a difference in 

 the distance of the great crossvein from the discal cell (which is 

 open in O. alpigena); but this distance is not constant in the same 

 species; in examining a considerable number of specimens of the 



i 



