Gr. F. Ferris and F. R. Cole 
191 
The clypeal region (hig. 7 C) lias the median portion separated by a pair 
of deep incisions fiom the lateral parts. 1 he front tarsi (Rig. 7 D ) differ from 
the others in the presence of short, almost spatulate setae on the first four 
segments. The wing (hig. < A) was figured by Speiser, but for the sake of 
completeness we are figuring it again. 
C, anterior portion of head; D, anterior tarsus. 
Genus Melophagus Linnaeus. 
An apology may be deemed advisable for discussing this well-known genus 
but oui attention has been attracted to it by the discovery of an apparently 
new foi m, and in connection with the description of this some general notes 
may not be out of place. Furthermore, as far as we have been able to deter¬ 
mine, there exists no illustration of any species of the genus that is of any 
particular value from a systematic standpoint. The crude figures that adorn 
the pages of most of our textbooks of parasitology, at least, can scarcely be 
regarded as pre-occupying the field, for at the best they show little more than 
the general characters of the genus. 
Massonat (1909) has discussed at some length the question of the homology 
of the small projection at each posterior angle of the thorax which some 
authors seem to have regarded as a haltere. He arrives at the conclusion that 
these structures are in reality vestigial wings and with this conclusion we are 
entirely in accord. In fact their position is such that they cannot be halteres 
unless a most remarkable shifting of the position of these organs has taken 
j place. They are to be regarded as almost the irreducible minimum of wing 
vestiges. No trace of the halteres can be found. 
