^. ONCODES 461 



Hereford (Tram Inn), and Shropshire (Wyre Forest), with dates ranging 

 only from July 10 to August 13. All of these localities are practically in 

 the southern part of England. The Hope Museum at Oxford has a 

 good series but unfortunately without histories except one well-marked 

 rather large female labelled "Donovan"; another rather large female is 

 immature and consequently has a paler abdomen, brownish thorax, and 

 rather brownish wings ; two labels are placed in proximity to the series, 

 a printed one bearing " albipes Mei.," and a MS. one " globula x'^ S." 

 It is recorded from Northern and Middle Europe. 



Si/iionj/m)/. — The first intelligible description of this species was that given by 

 Panzer in his Fauna Germanica, Ixxxvi., 20 (1803), under the name of Syrphus 

 globulus, and consequently I adopt his specific name. It may be true that Fabricius 

 intended to indicate this species in his Ent. Syst., iv., 311 (1794) under the 

 name of Si/i-phus o)-bicufus, but his description is absolutely unintelligible, and so is 

 every repetition of it until Wiedemann examined the type at Kiel and sent a more 

 detailed description to Meigen in 1822. I consider therefore that yl. or6?V»/i/s was 

 not really described until 1822, and I can never support the resuscitation of an 

 old unintelligible name identifiable only by reference to a type (which type may 

 easily have been transposed or replaced by a supposed better substitute), when in 

 the meantime an intelligible description, requiring no reference to a type, has been 

 given. If the examination of I'abricius' type in 1822 had revealed a species 

 unrecognised at the time of such examination and redescription a fresh description 

 would establish the species on a sound foundation and it would not matter if the 

 supposed Fabrician type were a changeling or whether the date of its origin was 

 1794 or 1822, but as a recognisable description accompanied by a name was given 

 in 1803 that must have priority over any description of 1822. I fully recognise the 

 law of priority for recognisable descriptions, but if it is to be enforced for 

 unrecognisable descriptions which may subsequently be made intelligible only by a 

 fresh description, then the sooner any attempt to make descriptions recognisable is 

 given up the better and let us fall back upon comparisons of types alone and burn 

 all our books. When I revived such a name as Platychirus sticticus Meig, I made 

 sure that Meigen's description was one which should have been recognised if 

 reasonable care had been exercised, but had his description been unrecognisable I 

 should have sunk his name as a synonym of F. sjyathvlatus Rond. or else have thrown 

 it into the limbo of nomina mala. 



A. orbicnlus {Fabr.) Wied. may therefore be considered a synonym of A. globtdus ; 

 A. tumida of Erichson described in 1840 froiu possibly Germany has never since 

 been recognised and has been sunk by Gerstaecker as another probable synonym. 

 A. borealis Zett. described from one specimen of uncertain sex taken in Lapland in 

 July 1822 is apparently only a dark specimen of this rather variable species, and 

 A. loita Gerst. from Sardinia rests at present rather uncertainly upon three 

 specimens. 



There might be some reasons advanced for identifying this species with Syiphus 

 globosmoi Fabricius (Syst. Entom., 770, 1775) which was descrdDed from England, 

 and which name is now applied to Cistogaster globosa (a species which is not known 

 to occur in England), but "frons ferruginea, Imea longitudinali nigra. Thorax 

 " antice ferrugineus " and " Pedes nigri " are prohibitive as regards Acrocera. 



2. ONCODES. 



Of/codes Latreille, Prec. Car. Gen. Ins., 154 (1796). 



Antennse placed on the extreme lower part of the head, and 

 ending in a long thin style or arista. Venation very imperfect. 

 Proboscis absent. 



Head of the male larger than that of the female, almost all eyes except for the 

 small vertex (on which are two ocelli) and the small space at the bottom of the head 

 on which are the antennae and the indistinct mouth parts ; frons slightly produced 



