56 [August, 



P. lONOTA, Eond. 

 Bolh males and females were bred by Mr. Inchbald in June, 1885, from the 

 flower heads of ragwort. 



PEGOMTIA, R. Desv. 



P. siLACKA, Meig., Schin., 



{olim P. diaphann, Auc). 



Mr. Verrall has recorded the capture of this rather rare species in Britain, and 

 since my last list was published I have found it myself near Bradford, as well as in 

 Oxfordshire, and have also received a specimen from Miss Prescott Decie, found near 

 Tenbury. This species has been mixed up by authors with the Mtisca flaveola of 

 Fallen, which it somewhat resembles. I placed the latter in the first part of my 

 list in the genus Mydcsa, but there have been great differences of opinion as to its 

 proper position ; Schiner arranges it among his Limnophoro'., under the specific 

 name of diaphana, and as the eyes in some specimens are slightly hairy, it has also 

 been classed among the Aricice. Under these circumstances I think it will be better 

 to place it, together with its congener (P. silacea), in the genus l^egomyia. Both 

 species have moderate and unequal sized scales to the alulets, and will therefore 

 come into my first division of that genus. Fallen and Zetterstedt place them next 

 each other, and the descriptions of these species have been so mixed up, that the 

 synonymy has become very confused. 



I had a most interesting correspondence at the beginning of last year with 

 Professor Mik, of Vienna, respecting these two species, and from the information 

 which I thus obtained, as well as from the interchange of specimens, I hope I may 

 be able to clear up the subject. In the first place the name diaphana has generally 

 been supposed to have been applied by Wiedemann to the less highly developed 

 species which we now propcise to call silacea ; but, on Prof. Mik examining the types 

 (of which he found three) in the Wied. Collection in Vienna, he found that they all 

 (though named diaphana) belonged to the more highly developed species, the M. 

 flaveola of Fallen. This being the case, Prof. Mik suggested to me that the name 

 diaphana had better be dropped, for it is really only applicable to M. flaveola, which 

 has a translucent abdomen, while the other has not, and it would lead to much 

 confusion to transpose the names entirely. Meigen having described the less highly 

 developed of these species in his 7th volume, under the name of A. silacea, and 

 Schiner having followed him, Prof. Mik thought that we had better adopt this title ; 

 he promised to publish some observations himself upon the subject, but as he has 

 not yet done so, I have pleasure in following his suggestion. 



Before endeavouring to clear up the synonymy, I think it will be better briefly 

 to point out the principal points of distinction between the two species, as neither 

 of them have been fully described. 



P. FLAVEOLA. — Frontal triangle in male mostly black, but occasionally red 

 (young spec. ?) ; eyes contiguous, and sometimes slightly pubescent ; frontal space 

 ill female occupying about one-third of the width of the head, and also mostly 

 black ; face glistening white in both sexes ; antenna; with two basal joints yellow, 

 and third joint black in both sexes ; arista shoi'tly ciliated, in some specimens 



