100 DIPTERA OF NORTH AMERICA. [PART II. 



newly coined name, with the usual latinized modification in Para- 

 clius, for the new genus which I intend to establish and to define 

 here. As our principal aim at present is an available generic 

 distribution of the already known North American species, I will 

 merely have the latter in view in establishing the characters of 

 Paraclius, and leave out G. leucospilus for the present. The 

 discovery of a larger number of related species will have to decide 

 whether the character of Paraclius is to be modified so as to admit 

 species like G. leucospilus, or whether a new genus is to be founded 

 for such species. 



The following are the characters of the genus : The first joint 

 of the antenna; hairy on the upper side ; third joint of the antennae 

 rounded ; arista dorsal, with the ordinary pubescence, not feathered. 

 Face of very moderate breadth, narrowed towards the mouth, not 

 convex in its lower part and not reaching to the inferior corner of 

 the eye. The first joint of the hind tarsi without bristles. The 

 last segment of the fourth longitudinal vein, beyond its middle, is 

 bent forward in a rounded angle, thence running in a curve, with 

 the concave side turned backwards, towards the margin of the 

 wing, and reaching it quite near the tip of the third longitudinal 

 vein, so that the first posterior cell has but a small opening. Hy- 

 popygium entirely disengaged, not prolonged, with a very short 

 pedicel, so as to appear sessile or nearly so ; the exterior append- 

 ages lamelliform. 



The characteristic differences between Paraclius on one side 

 and Gymnopternus and Pelastoneurus on the other, will be easily 

 § understood from the foregoing. Besides the species of the latter 

 two genera, there are those of the genus Hercostomus, which re- 

 semble the species of Paraclius ; but in this genus the last seg- 

 ment of the fourth longitudinal vein only very gradually approaches 

 the third longitudinal vein, without any vestige of an angular 

 flexure, and reaches the margin of the wing not so near the third 

 longitudinal vein. 



Only American species of Paraclius are as yet known. The 

 name of the genus (from napa — x%nu, I close), means that the first 

 posterior cell of the species is almost closed. 



