202 THE CANADIAN ENTOMOLOGIST 



Fausta as a subgenus for the inclusion of the generalized nemorum Meig. and by 

 retaining Mctaphyto Coq. as a subgenus for the inclusion of gcnaUs Coq. 

 Relationships of the Nearctic and Palaeakctic Species of the Genus 



Ernestia s. str. 



From an examination of five palaearctic species it would appear that 

 while some of the nearctic species are very closely related to palaearctic species, 

 yet there are perhaps no two species common to the two land masses- A more 

 extensive study of the European material may, of course, serve to modify this 

 statemen.t. It may be of interest to point out the difference between the 

 European species I have examined and their nearctic relatives. 



A male specimen of B. ntdis Fall, so determined by Bezzi, has no keel- 

 like jM-ojection on the basal part of the inner forceps, and in this respect re- 

 sembles E. flaricor)iis of Brauer and my E. frontaJis. It differs from the for- 

 mer in not having a bright yellow third antennal segment and from the latter in 

 having the width of the front at the narrowest place equal to less than the 

 length, of the second antennal segment. 



A male specimen of E. radicuin, so named by Brunetti, has a keel-like 

 projection on the basal part of the inner forceps in such a rudimentary condi- 

 tion that it can only be seen by careful scrutiny. It dift'ers from B. flcuvicornis 

 Br. in the color of the third antennal segment ; from E. frontalis in the notably 

 shorter inner forceps of the male genitalia and from E. iiiyroconica in the 

 narroMfer facialia. 



A male specimen of E. coiuilz'cns Zett.. so named by Bezzi, is evidently 

 very closely related to my nigropalpis and arciiata In nlgropalpis, however, 

 the tips of the outer forceps are laterally compressed so as to be bayonet-like in 

 shape; and in arcnata the fifth tergum is much longer and more clearlv defined. 



A male specimen, named E. consobrina Meig. by Bezzi, has a median 

 keel-like projection on the base of the inner forceps that is split longitudinally 

 into two halves, very much as in the case of my bicarina. In the latter species, 

 however, the splitting process has been carried considerably further; and also 

 each prong of the fifth sternite terminates in a short spine, which is not the case 

 in consobrina. 



There is a male specimen from Shirmer, labelled "Berlin, Germany," 

 that has not been identified. It runs in my key to section 10 but it can be read- 

 ily separated from all the nearctic species on account of the extraordinary 

 length of the median keel-like projection, on the base of the inner forceps. 



Distribution of the Genus Ernestia. 



Our knowledge of the distribution of the genus Ernestia in the Southern 

 Hemisphere is too meagre to warrant any conclusion concerning the origin 

 and development of the gronp for the whole world. For the Northern Hemis- 

 phere, however, our knowledge of the distribution of the group is at least fairly 

 complete. In his catalog of palaearctic Diptera, Kertesz lists twenty-three 

 species, while for North America we now have sixteen species ; . consequently, 

 palaearctic rather than a nearctic origin is indicated, although, of course, by 

 no means proven. 



Further light is thrown upon this cpiestion by reference to the degree 

 jf specialization of the species in the respective regions. We have already 



