INSECUTOR INSCITI^ MENSTRUUS 119 



NOTES ON HELOMYZID-^ AND DESCRIPTIONS 

 OF NEW SPECIES 



(Diptera) 

 By C. B. D. GARRETT 



The local conditions at Cranbrook, British Columbia, seem 

 admirably adapted to the life of the dipterous family Helo- 

 myzidse, which is borne out by the number of species found 

 here and the great abundance of some. Thus in studying the 

 family I have examined several thousand, and numbers usually 

 tend to show what amount of variation should be expected in 

 each species. The classification of earlier works has been 

 based chiefly on the humeral and dorso-central bristles ; but 

 specimens before me show the unreliability of these features, 

 which have also been at least in part the cause of new genera 

 being erected that have fallen as synonyms, and in some cases 

 the dorso-centrals vary as much as 50 per cent and in others 

 from 5 to 15 per cent. Another weak feature of this classifica- 

 tion is that the dorso-centrals throw into a single genus two 

 or more insects of quite distinct structure and in some cases 

 three distinct forms of the male genitalia. Thus starting for 

 my own satisfaction a new classification in my cabinets I soon 

 realized its apparent reliability and distinct benefit, so after 

 careful consideration and thought I would offer it for the 

 adoption of others. In collections containing a large number 

 of the North American forms the proposed classification will 

 clearly show how the special types of male hypopygium are 

 thrown in convenient groups, at the same time into distinct 

 genera on other features, a benefit that is not easily over- 

 looked. 



The main feature of the new scheme is based on the fore- 

 most (next the antennse) fronto-orbital bristle, and in the 

 hundreds that I have examined in no case did I find it to vary, 

 excepting in one species in which no two specimens seem ex- 

 actly alike. This species is easily separated by other char- 

 acters, and cannot be the cause of any trouble. In the genus 

 Anorostoma Loew, three American species fall into one genus, 



