TAXONOMY OF MUSCOIDEAN FLIES — TOWNSEND 103 



Length, 7 to 9 mm. Differs from C. aurifrons Townsend by hav- 

 ing the anal segment wholly deep golden, same shade as para- 

 frontals, etc. ; humeri with a faint, abdomen with a more distinct 

 golden tinge, scutellnm hardly more narrowly testaceous, and thorax 

 more distinctly vittate. 



Type. — Cat. No. 11,650, U. S. N. M. (female, Harrison, Idaho). 



EUDEXODES, gen. nov. 



This genus is proposed for Dcxodes eggeri Brauer and von Ber- 

 genstamm, of Europe. The characters of the facial plate throw the 

 species into a different tribe (if not subfamily) from D erodes, of 

 which the type is spectabilis Meigen. 



Subfamily Willistoniin^e 

 Genus Belvosia Robineau-Desvoidy and allies 



Dr. Williston published a plate of Belvosia and allies in Insect 

 Life, vol. v (1893), facing p. 238, exhibiting the difficulties to be en- 

 countered in separating the forms. By studying this plate, it will 

 be seen that there is a correlation between length of second antennal 

 joint and bristles on the facialia, also between former and distance 

 of vibrissa? from oral margin. 



The more elongate the second antennal joint is, the less bristles 

 there are on the facialia. Conversely, the shorter the second joint, 

 the more strongly are the facialia ciliate. In all cases, the distance 

 of the vibrissa? above the oral margin is about equal to the length of 

 the second antennal joint. 



The forms having facialia not ciliate 'have the second antennal 

 joint long, vibrissa? inserted far above oral margin, and fourth vein 

 angular at bend. Those having facialia ciliate have the second joint 

 much shorter and vibrissa? inserted only a little above oral margin ; 

 they fall into two categories by the character of the bend of fourth 

 vein. We thus have the following table : 



1. Facialia not ciliate, fourth vein angular at bend; second antennal joint 



strongly elongate, nearly as long as third joint; vibrissa? inserted high 

 above oral margin, male claws normally very elongate, female claws 

 less elongate. (Sto. Domingo, Brazil, California, New Mexico, 



Mexico, Jamaica.) Belvosia bicincta Robineau-Desvoidy 



Facialia ciliate 2 



2. Fourth vein bent at a sharp angle, with or without stump, but often 



V-shaped and with stump; claws of male normally elongate, of female 

 not; second antennal joint not strongly elongate, vibrissa? inserted 

 normally above oral margin. (Brazil.) . . . Willistonia esuriens J. C. Fabricius 



