FLIES OF THE GENUS OGCODES — SCHLINGER 235 



Northwest Passage between Siberia and Alaska. There appears to 

 be no evidence for assuming the presence of a one-time Antarctic land 

 bridge to explain this distribution as has been the case with some 

 other authors confronted A\dth similar distribution problems. Species 

 of the Australian-Nearctic-Neotropical distribution pattern have 

 maintained a temperate, discontinuous distribution, and no doubt 

 representatives of this group will be found to occur in China and 

 other temperate East Asian countries. A similar cross-continent tem- 

 perate distribution pattern occurs between the Nearctic, Palaearctic 

 and Ethiopian regions. 



From the evidence at hand it seems that the genus Ogcodes is best 

 adapted to the temperate areas, both in numbers and species. How- 

 ever, further collecting in tropical areas may show them to be equally 

 well inhabited. For further notes on distribution see the discussions 

 under the various species in the text. 



Phylogeny 



Because many of the world species were not available for study, and 

 because their descriptions did not contain the essential features 

 necessary to account for their phylogenetic position, the phylogeny 

 presented herein is obviously preliminary with the possible exception 

 of the Nearctic fauna. Text figure 2 shows the probable relationships 

 based on the species studied, which represented about 60 percent of 

 those now known. No doubt other subgenera and species groups 

 may have to be set up at a later date, but at least an account of our 

 present knowledge of the genus can now be shown with some degree 

 of certainty. 



A new South African genus appears to be the last traceable ancestor 

 of the highly evolved genus Ogcodes. Since this undescribed genus 

 possesses such features as a distinct proboscis, strong wing venation, 

 and hairy eyes, it probably gave rise indirectly to the monotypic 

 Chilean genus Thersitomyia Hunter, which, according to its original 

 author (Philippi, 1871, as Thersites), was very similar to Ogcodes 

 except in having hairy eyes. 



Of the subgenera of Ogcodes, the new subgenus Protogcodes seems 

 to retain the most primitive characters, such as stronger wing vena- 

 tion and more styliform antenna with a basal bristle, and judging 

 from the relationship of 0. brunneus (Hutton) with 0. (P.) paramonovi, 

 new species, I have assumed that the brunneus group is the most primi- 

 tive one of the subgenus Ogcodes. There is little doubt that the 

 eugonatus group originated from that of brunneus, and simply lost 

 vein Ml and crossvein m-cu. Just where the borealis group originated 

 is questionable, but the presence of vein Mi and crossvein m-cu, and 

 male genitalia of the brunneus-eugonatus types as well as exemplifying 



