2 PROOEEDIISrGS OF THE NATIONAL MUSEUM vol. 80 



In 1929 I had the opportunity to examine most of Walker's type 

 specimens, although in the time at my disposal I did not see all of 

 them. The object of the present paper is to report the results of 

 this work and to indicate as far as possible the available names of 

 the species Coquiilett had before him, in those cases where he erred 

 in his identification of Walker. Species of which I did not see the 

 types are also included, with such explanations as I can offer from 

 the much larger collections now available and the advances in classi- 

 fication that have been made in recent decades. They are listed under 

 Walker's names, and in the order of Coquillett's work, although in 

 this arrangement I am obliged to begin with a series in which I did 

 not see the tj^pes. 



I am under obligation to the authorities of the British Museum, 

 especially to Maj. E. E. Austen, D. S: O., keeper of the division of 

 insects, for the privilege of examining this important material. 



Only species from the region north of Mexico are here discussed. 



Gymnosonia par Walker, List, p. 692. Coquiilett (p. 43) made 

 this a synonym of G. fuUginosa Robineau-Desvoidy. Type not seen. 

 The genus is a striking one, and but one species is known from the 

 Eastern States; no one has questioned the correctness of Coquillett's 

 identification. 



Gymnosoma occidua Walker, List, p. 692. Coquiilett (p. 43) 

 placed this as a synonym of Cistogaster ivmiaculafa Macquart. 

 Townsend ^ discussed imm^acul ata and thought he could make out a 

 division of the abundant material into two forms, but left occidua 

 as a synonym of hnniaoulata as it had been placed by Coquiilett. 

 Later ^ he decided that occidua is the valid name for one of the forms, 

 immacidata for the other. He took up the subject again in his 

 Taxonomy of the Muscoidean Flies,^ where he redescribed occidua 

 in both sexes and referred it to the genus Gymnoclytia Brauer and 

 Bergenstamm. The type of the genus is divisa Loew, the only 

 included species, which is believed to be a synonym of occidua. The 

 generic characters are slight, and there is room for difference of opin- 

 ion as to whether it is not a synonym of Cistogaster. The genotype 

 of the latter is the European gJohosa Fabricius, which has the petiole 

 of the apical cell ending in the exact tip of the wing, and also has a 

 less protuberant oral margin. Walker's description of the abdomen 

 seems ample to fix the form he had. I did not see his type. 



Hyaloniyia occidentis Walker, Insecta Saundersiana, p. 260. 

 The description is less than five lines long. I did not see the type. 

 Coquiilett (p. 44) believed he had recognized the species and referred 



1 Trans. Amfer. Ent. Soc, vol. 22, p. G6, 1895. 



2 Aim. Mag. Nat. Hist., ser. 6, vol. 19, p .SI, 1897. 

 aSmilhsoniau Misc. Coll., vol. 51, p. 127, 1908. 



