244 [Octolier, 



by Dr. D. Sharp, F.R.S., on June 1st, 1901, in a decaying holly tree 

 at l^ank, by Lyndhiirst, New Fore!>t, Hants. Dr. Sharp was so <i,oocl 

 as to send me two sejjarate consinrnnionts of larv?e and pupa?, the first 

 on June Gth, the second on .Tune 11th ; the three males emei'ged on 

 June 8th and 9th. one female on the 15tli, three other females on the 

 I8th and 19th, and yet another on the 28th. 



As to the circumstances under which our specimens were ob- 

 tained, the following; extracts from Dr. Sharp's letters may be of 

 interest. Writing from Bank on June 9th, 1901, Dr. Sharp said : — 

 " I went to the tree immediately after breakfast this moriiinp^, as so 

 many Dipfera appeared yesterday for the first time that T thought 

 these little creatures might be all gone. T am glad this was not the 

 case. T at once secured two immature flies under the bark, and a few 

 puparia. Many larv?e of sizes going down to about 1 mm." In a 

 second letter frrtm the same address on June 19th Dr. Sharp wrote: — 

 " T have no belief in this fly being found again — certainly not above 

 once in thirty years, and probably never here The conditions are 

 those of our rarest British beetles, such ns Eucnemis.'" It is to be 

 hoped that Dr. Sharp's fears may prove groundless, and that the species 

 may be reported ere long from other localities in the British Islands. 



In liis papor on the European species of Tachijgaster* pp. 264, 267, Loew 

 states that Facliygaster argentlfer {arfjeiitifpra), Ja3nnieko (Berl. ent. Z., X [1866], 

 p. 221), is a synonym of P. meromelcena, Duf. This, however, cannot be so if my 

 interpretation is correct, since Jaennickc states that in his species the halteres in the 

 $ are blackish with black peduncle, thougli wliilc in the ? . Moreover, the size 

 that he gives (2^ mm.) is too small for P. meromelcBiin. and, although he describes 

 both sexes, he gives no indication that the eyes are separated in the S ; the eyes in 

 the $ , and appai-ently in that sex alone, are bordered with silver just as in P. mero- 

 melcena. Jrennicke states that lie has bred both sexes of P. argentifera, and says 

 that the ? is much more common than tlic g . 



With reference to P. meromelfena, Duf., Loew writes (/oc. c<7., p. 266), "Of 

 this species I possess a ? from Herr Dufour's collection, two 9 ? from Germany 

 agreeing with it, and a S taken near Magdeburg ; that the latter belongs to the 9 

 of Pachygaster meromelas, in spite of the black coloration of its halteres, which are 

 white in the ? , I do not doubt, in view of the agreement in all other characters." 



One is naturally loth to differ from so great an autliority as 

 Hermann Loew,* and it is only after long and anxious consideration 

 that I have come to the conclusion that the three specimens described 



* H. Loew, " Revision der europiiischen Paclivgixstcv-Arteii ;" Zoitscliiift fiir die Gesammteii 

 Naturwi.s.sen.schaften, Bd. XXXV [1870], pp. 257—271. 



* Even Homer nod.'i, however, and if further ilhi.stration of the well known fact be needed, 

 it may be observed that in ln.s remarks on Soliiner's ;>tatotnent that in Pachycmater Leacliii, witli 

 the exception of the entirely hyaline wings and wholly yellow lega, all else is "as in P. nter," 

 Loew [Inc. cil., p. 2G1) gives no indication that he himself has noticed the difference in the shape 

 of the head. 



