2 PROCEEDINGS OF THE NATIONAL MUSEUM vol.6!* 



distinguishing characters, one is led to a better appreciation of the 

 relationships of the forms found in the different faunal regions, 

 which is an impossibility under the old system. A complete eluci- 

 dation of the generic groups is not possible at this time owing to 

 lack of material, but it is hoped that the data in this paper may 

 throw some added light on the problem. 



The family Supromyzidae is very similar to Sciomyzidae, differ- 

 ing from it essentially only in having the postvertical bristles in- 

 variably more or less convergent, sometimes cruciate, and the sixth 

 vein of the wing always falling short of attaining margin of wing, 

 the more typical forms having the vein very short and quite 

 abruptly discontinued. 



It appears to me that these characters are rather unimportant 

 for separating families upon, especially as some Sciomyzidae have 

 the sixth vein evanescent at tip and I am more incKned to consider 

 the groups as subfamilies than separate families. This is the more 

 impressed upon me when I come to consider the status of the group 

 for which Dr. F. Hendel has recently erected the family Peris- 

 celidae. In his family he, I infer, has included but one genus, Peri- 

 scelis Loew, which genus I included in Sapromyzidae in the paper 

 already referred to above, but the inclusion of three other genera in 

 the group in the present paper does not convince me that they are 

 entitled to family rank. All have the postvertical bristles divergent 

 and the sixth-wing vein incomplete, being in these respects inter- 

 mediate between the normal forms of Sapromyzidae and Sciomy- 

 zidae. All the four genera also have the auxiliary vein of wing in- 

 complete, which character is not in keeping with the definition of 

 the larger group in which they have been placed by Hendel, but 

 they are in habitus very similar to many Sapromyzidae and the 

 general wing characters are otherwise as in Steganopsis to a very 

 marked extent in one or two of the genera. 



I incline to the opinion that these groups should form subfamilies 

 of Sapromyzidae, but beyond expressing this opinion do not intend 

 to discuss the matter at this time. 



I present in this paper a synopsis of the four genera of Perisce- 

 linae as no such synopsis is in existence up till this time. 



Subfamily Sapromyzinae 



A partial synopsis of genera of this subfamily is presented on 

 a subsequent page in this paper, and indications of relationships of 

 new genera are invariably given where such genera are erected. 



XENOPTERELLA, new genus 



Generic characters. — Differs from all other genera in this family 

 in possessing two transverse veins between the third and fourth longi- 



