TAXONOMY OF MUSCOIDEAN FLIES — TOWNSEND 5 1 



Syiithcsiomyia has strong hypopleural hairs, which can hardly be 

 considered true bristles, yet they serve as a character of equal value. 

 It has also a bare arista. It lacks the pteropleural hairs and bristles. 



Musca, Glossina, PseudopyreUia, Pyrellia, Morellia, and Dasy- 

 phora ( ?) have the Muscoidean type of venation strongly marked 

 (except Pyrellia), but possess no hypopleural bristles. Glossina and 

 Musca, however, possess distinct pteropleural bristles like the other 

 Muscoidea, while PseudopyreUia, Pyrellia, Morellia, and Dasy- 

 phora (?) possess a tuft of more or less bristly hairs in their place, 

 directly beneath the wing bases. Morellia hortorum has ptero- 

 pleural bristles approaching those of Glossina and Musca in strength, 

 and is doubtless not a true Morellia, which has only a tuft of ptero- 

 pleural hairs. All these genera are more or less intermediate, but 

 they can be distinguished by the above characters. 



Some doubt may arise with Myiospila, etc., which belong in the 

 Anthomyioidea. They have neither hypopleural nor pteropleural 

 hairs, which will always distinguish them, and it may be seen that 

 the fourth vein is continuous with wing margin behind the middle 

 point of the rather widened apex of wing. 



In connection with the characters given for the Muscoidea in the 

 table, it is to be noted that the fourth vein is incomplete in certain 

 genera, as Roeselia, Pliytouiyptcra, Thrixiou, Gastrophilus, Sylle- 

 goptera, Euryccromyia, Dichcetoucura, etc. 



Finally it may be pointed out that certain species of the old genus 

 Cyrtoneura, referred to Pararicia by Brauer and von Bergenstamm, 

 and belonging to the Anthomyioidea, show the gentle removal of the 

 fourth vein from the wing margin which is characteristic of the 

 forms whose position has been heretofore misunderstood. These 

 forms were considered by some authors as belonging to the old 

 Muscidae s. str., and by others as belonging to the Anthomyiidae, but 

 the characters pointed out by Girschner serve to reveal their true 

 position. They are distinctly to be considered as a genealogical 

 group descended from forms with a wholly straight (as far as wing 

 margin) fourth vein. The extensive removal of the fourth vein 

 from the wing margin in Pyrellia, Mesembrina, et al. must be con- 

 sidered as a further step in the development of the venation toward 

 the Muscoidean type. The Muscoidea are without question more 

 specialized than the Anthomyioidea; and since the form normal in 

 the latter exhibits the type of venation universal in the Holometopa 

 (excepting the Conopidae), the last named subsection is less special- 

 ized than the Schizometopa. The Conopidae stand evidently to one 

 side as a large group rather closely related to both the Schizometopa 

 and the Holometopa, but with a preponderance of affinities for the 



