8 ARKIV FÖR ZOOLOGI. BAND 13. N:0 6. 



wing-pattern of the majority of the species shows a curious 

 monotony of pattern that is remarkable when we learn that 

 more than one group of the genus is involved. The costal 

 cell is unmarked, exeept for a seam at the humeral cross- 

 vein, but the subcostal cell usually shows a series of brown 

 markings that are darker than any of the other areas of the 

 wing, being deeper, or at least as deep, in color, than the 

 stigmal area; the remainder of the wing-surface is variously 

 mottled and marbled with brown, gray and subhayaline, ac- 

 cording to the species. A few species (T. patagonica, T. 

 fuegiensis) have the ground-color of the wings dark, sparsely 

 variegated with subhyaline. Other species (T. rufirostris 

 BiGOT, T. ona, T. philippiana Alex., T. chilensis) have the 

 wings dark, longitudinally streaked with hyaline, this inclu- 

 ding a medial streak extending the length of the wing, cell 

 E5 being entirely påle (almost as in certain members of the 

 tricolor group of the Nearctic region). The hypopygia of the 

 species of Tipula from the region under consideration vary 

 in structure according to the group but all of the species 

 known to the writer bear a median appendage on the eighth 

 sternite and the shape of this structure offers one of the 

 best means of specific identification. The ovipositor of the 

 female in practically all cases has the tergal valves long and 

 slender, arising from a long, shiny dorsal shield, and with 

 the margins of the valves quite smooth; the sternal valves 

 are of various lengths, in some species being very short, in 

 others almost attaining the ends of the tergal valves. 



The following key well be of some service in separating 

 the closely related species of Tipula from the region consi- 

 dered by this paper. 



1. Wings nearly hyaline or faintly tinged with gray, 

 the post-stigmal subhyaline area little conspicuous. 

 (Santa Cruz, Southern Patagonia). T. wittei Alex. 

 Wings not as above, streaked longitudinally with 

 brown and white or else heavily marbled with brown, 

 gray and påle markings. 2. 



2. Wings longitudinally streaked, or else with the 

 ground-color dark with the påle markings very small 

 and sparse. 3. 



Wings heavily and distinctly marbled. 10. 



