350 



CHARLES T. BRUES. 



which bears a dorsal or terminal arista composed of three joints. 

 When examined more closely, however, and more especially in 

 longitudinal section, it is seen that this large segment is complex 

 (see Fig. i) and consists of a smaller joint almost entirely con- 

 cealed within a larger outer one. These two are attached to the 

 head by a third small and partially concealed segment. Such an 

 arrangement is constant throughout the Phoridae and is, so far as 

 I know, absolutely unique among Diptera. 



The nomenclature and homology of these joints has been 

 interpreted in several ways. Wandolleck ('98) has considered 

 the antenna to be six-jointed without attempting to homologize 

 the segments with those of the antennae of other 

 Diptera. The majority of recent dipterists seem 

 to have accepted a nomenclature which would 

 regard the three large basal joints as homologous 

 with the three segments of the typical brachyce- 

 rous antenna, the apical one supplied with an arista 

 of the usual kind. The third interpretation sug- 

 gested in the paper before referred to by Williston 

 ('06) is that the basal portion consists of two joints 

 only, and that the arista so-called really represents 

 the whole flagellum of the nemocera. Schiner also 

 refers to the antenna as apparently two-jointed 

 ('64, p. 335), but on page xv he says in more 

 detail: " Fuhler nahe am Mundrande eingefugt, 

 scheinbar zwei-gliedrig, das dritte Glied rund (bei 

 Coniccra kegelformig), mit nackter oder doch nur 

 pubescenter Riicken- oder Apicalborste." It is 

 thus evident that he takes them to be actually three- 

 jointed, and in this view I fully concur. From 

 the examination of large numbers of mounted 

 specimens representing most of the described 

 3, antennal joints; species, as well as several in microscopical section, 

 A, arista. anc j a number of published figures, I am fully con- 



vinced that there are always three distinct joints, the large apical 

 one of which bears an arista. 1 



1 Whether we conceive the arista to be a modified portion of the nemocerous flag- 

 ellum would in this connection be a problem apart from the relationship of the various 

 brachycerous families among themselves. 



FIG. I. 

 Antenna. 



