( 249 ) 



?»»oi-'»y 



^^b'M "JU120 1942 



XXI .-^J^^^lMrt^_*i- 



A PRELIMINARY LIST OF HERTFORDSHIRE DIPTERA. 



Bj A. E. GiBBs, F.L.S., F.E.S., and Philip J. Barraud, F.E.S. 



Read at Watford, 23rd April, 1907. 



In presenting to the Society the following list of Diptera 

 observed in our County, we wish to express our hearty thanks to 

 the Kev. E. N. Bloonifield, M.A., F.E.S., of Guestling, Hastings, 

 who has given us very great assistance in the identification of 

 specimens, and valuable advice in the preparation of this list ; 

 to Mr. E. E. Austen, of the British Museum (Natural History), 

 who has rendered most useful help during the examination of 

 the collections in the Museum ; also to the Hon. N. Charles 

 Rothschild, M.A., F.L.S., F.Z.S., who kindly prepared the list 

 of Pulicidae met with at Tring, and to others who have sent 

 us records of captures. 



By far the greater number of records have been obtained from 

 the very extensive collection of flies captured by Mr. Albert 

 Piffard, of Felden, Boxmoor, Avhich is now in the British 

 Museum. This collection was formed din-ing the last decade of 

 the nineteenth century, and contains many thousands of specimens 

 which are carefully labelled with the date and place of capture, 

 and are mostly named by Mr. Piffard. Nearly all the specimen^ 

 were taken in the immediate vicinity of his home. This mass of 

 material is being gi'adually incorporated in the new collection of 

 British Diptera at the Museum, each specimen before finding its 

 permanent resting-place in that collection, being examined and 

 its determination verified by Mr. E. E. Austen. For our know- 

 ledge of the existence of this collection we are indebted to the 

 Rev. E. N. Bloonifield. 



In the following list all the Felden records, except in a few 

 cases where another observer's name is attached, are Mr. Piffard's, 

 and the names of flies taken by him in other localities are followed 

 by his initials (A. P.). The larger number of his specimens are 

 in a cabinet containing the unincorporated accessions, and have 

 not yet been critically examined by Mr. Austen. These are 

 marked in our list with an asterisk (*), and the determination 

 is Mr. Piffard's. When several examples of the same species 

 were found, we have mentioned the date of the earliest capture 

 only. When a species is mentioned as occurring in Hertfordshire 

 by Mr. G. H. Vei-rall in his book on ' British Flies,' a work in 

 course of publication, we have appended the word ' Verrall ' to 

 Mr. Piffard's record. Doubtless these specimens have been 

 examined by Mr. Verrall. A considerable proportion of those 



VOL. XIII. — PART IV. 19 



