]921.] 95 



such characters can hardly be better exemplified than by the group 

 of species now included under the generic term Limnophora. This 

 group of obviously allied species includes those with the eyes in the 

 male touching on the frons, and in others as widely separated as in 

 the female ; species with the arista practically bare, pubescent, or sub- 

 plumose ; species with the eyes distinctly hairy and others with the eyes 

 bare. This wide range of variation in those characters considered by 

 many previous students as of generic value, accounts for certain species 

 having been included hj some writers in other genera such as Sjjiloffaster 

 and Coenosia. 



The group of Anthomyids included under Limnophora in its widest 

 sense ma}' be shortly characterized as follows : — 



Thorax with two pairs of presutural dorsocentral bristles, no prealar 

 bristle and sternopleural bristles 1 : 1 or 1 : 2, but never arranged in an 

 equilateral triangle. Anal vein not reaching to margin of wing, spine 

 at mediastinal break in costa usually very small and insignificant. 

 Hind tibiae without the dorsal bristle such as is present in, for example, 

 Phaonia (= Hyetodesia'). Arista usually almost bare, at most only 

 occasionally with the hairs above and below together as long as third 

 antennal joint is deep. Abdomen usually with pairs of triangular or 

 trapezoid dark markings. Legs in British species always black, with 

 simple front femora. 



This definition includes Spilo^aster nigrinpi'vis Zett., S. macu- 

 losa Mg., and S. notata Fin., and the species of Melanocliila of Yerrall's 

 "List" in addition to the whole of his species of LimnopJiora. Some 

 of them bear a considerable resemblance to the black -legged species of 

 Mydaea (^Spilogaster), but may always be distinguished by the smaller 

 number of sternopleural bristles (often 2:2 in Mydaea^ or by the 

 absence of the prealar bristle. Others resemble species of Li'spe, but 

 the facial orbits are bare, the palpi not conspicuously dilated at the tip, 

 and the pteropleura without bristles. 



Many attempts have been made, especially in recent years, to split 

 off from Limnophora some of the more aberrant species as distinct 

 genera or subgenera, and in many cases there appears to be justification 

 for this course, but in none of these attempts has use been made of the 

 following characters which will be found to divide the group into at 

 least two natural divisions. If the base of the cubital vein be examined, 

 it will be found in many species to be quite bare (Division I), while in 

 others there are always small bristles, at least on the nodose junction 

 with the radial vein, and usually both on the upper and the under side ; 

 while in all the species with the cubital vein thus armed, known to the 



