Clare Island Survey. 



25 

 DIPTERA. 



By PERCY H. GRIMSHAW, F.R.S.E, F.E.S. 



Read November 11. Published December 9, 1912. 



Introduction. 



The following list of the Diptera of Clare Island and the surrounding mainland 

 is the result of the examination and determination of over 4,000 specimens. 

 In addition to the material obtained by myself during a few days' visit to the 

 island in July, 1910, and a sojourn of about a fortnight in the neighbourhood 

 of Westport exactly a year after this date, I have had the advantage of 

 working through collections made by other entomologists, notably Mr. J. N. 

 Halbert, Mr. Claude Morley, and the Rev. W. F. Johnson. In the list which 

 follows, the name of the collector is indicated in every case within paren- 

 theses, and to all those who have thus assisted me I hereby tender my hearty 

 thanks. 



Of the 519 species here recorded no fewer than 160, or more than 30 per 

 cent., appear to be new to the Irish fauna. These additions are indicated by 

 an asterisk (*), while five species which are new to Britain have their names 

 preceded by a double asterisk (**). In this connexion I must here express 

 my great indebtedness to Professor G. H. Carpenter, who lent me one of 

 VerraU's Lists of British Diptera, marked and most generously placed at his 

 disposal by Col. J. W. Yerbury, showing what species were already recorded 

 for Ireland. Without this help I should have found it a very troublesome 

 task to ascertain which of the following species were new to the country. 



With regard to the summarizing of results I feel it to be somewhat 

 premature to pronounce any definite opinions on the question of distribu- 

 tion. Our knowledge of the Dipterous fauna of Ireland is very far behind, 

 and with prolonged periods of collecting any conclusions now formed might 

 be entirely upset. The following remarks are therefore only to be taken as 

 suggestive. In the first place, our knowledge of Irish Diptera is in the main 

 drawn from the records of A. H. Haliday, who appears to have collected 

 chiefly in the eastern counties. The only paper of any importance dealing 

 with the western counties is that by Colonel Yerbury on the Diptera of 

 B.I. A. pkoc, vol. xxxi. A 25 



