24 THE DIPTERA-BRACHYCERA OF TASMANIA, 



form almost the only distinguishing character. On the 

 other hand, the antennae of rhycua imitans and of Ecti- 

 norrhynchtu phyciformis are so much alike that they 

 might easily be placed in the same genus, whereas an 

 examination of the other characters shows that there is 

 very little relationship between them. Although, how- 

 ever, the form of the antennas is of little use in classify- 

 ing the genera, it is yet of great value in distinguishing 

 the different species. The situation of the antennae, how- 

 ever (whether arising from the middle or lower part of 

 the face), is a satisfactory generic character. 



In classifying the genera the form and venation of the 

 wings seems to me to be of great importance. In the 

 classification here adopted a single wing is all that is 

 necessary in order to ascribe any species to its correct 

 genus. The wings may have the fourth posterior cell 

 either open or closed, may be large and broad or short 

 and narrow, may have the veins faint or very promi- 

 nently marked, and may be hyaline or banded with black 

 or brown. Next in importance to the wings as a generic 

 character comes the relative positions of the eyes, which 

 may be widely separated in both sexes, or joined, or 

 closely approximated, in the male and widely separated 

 in the female. Finally, the form of the proboscis is of 

 considerable importance; this may project prominently 

 forwards, lie close against the face, or be altogether con- 

 cealed within the oral aperture ; this character, however, 

 must be used with a certain degree of caution, as not 

 infrequently a genus may contain an aberrant species 

 which differs considerably in the form of the proboscis 

 from the more normal species, although it agrees with 

 them in its other characteristics. 



A curious secondary sexual character that occurs in 

 certain males of Ectinnrrhynchux and Psiloeephala is a sil- 

 very shimmering tomentum that covers all or part of the 

 dorsal surface of the abdomen. This character makes the 

 males very conspicuous when in flight; it is altogether 

 wanting in the females. 



The s-peeies belonging to this family are usually slug- 

 gish in their habits, and may more usually be mil with 

 at rest than on the wing. A number of species may 

 be found settled on the ground in sandy places, whilst 

 others frequent lops, tree trunks, or low vegetation. The 

 malea of Ectinorrhynehua variabilis may be found dancing 

 in the air with their long hind leers hanging down. Several 

 of the species bear a resemblance to Hymenoptera, the 

 resemblance being increased by a curious habit possessed 



