STSTEOPUS. 157 



A Germ rufipes, Macq. Dipt. Ex. Suppl. i. p. 119, has been described from Yucatan, 

 Mexico. 



SYSTROPUS. 

 Systropus, Wiedemann, Nova Dipter. Gen. Icon. 111. (1820) . 



Authors are silent about the sexual difference of Systropus. The only one who 

 approaches the subject is Loew (cf. Dipt. Siidafr. p. 200), who confesses that he is in 

 doubt about the sexual differences in this genus. The examination of the specimens 

 before me proves that both sexes have contiguous eyes, Systropus shares this character 

 with the " Cyrtidse," certain " Blepharoceridse," and with Orphnephila. In the female 

 the eighth abdominal segment is flattened from the sides, and ends on the underside in 

 two little points, between which is a (probably double) projecting lamel. In the male 

 there is a distinct ninth segment, with a circular opening at the end, within which the 

 male appendages are visible. 



The following synoptical table of the species of American Systropi at present known 

 is constructed principally from descriptions, and should therefore be used with caution 

 [Systropus (?) chilensis, Philippi, is omitted, the data necessary for its insertion in the 

 table not being sufficient] : — 



Abdomen black at both ends, red in the middle macer, Loew, infuscatus, 



angulatus, and imbecillus, Karsch ; all from the United States. 

 Abdomen not black at both ends, red in the middle. ^^tWi D 



Front legs yellow. ^ / H 



Hind legs altogether black nitidus, Wiedem. (syn. brasi- I'^fn 



liensis, Macq.); Brazil. 

 Hind legs not altogether black. 



First joint of the hind tarsi yellow. 



Hind femora black at the tip; tibiae yellow at 



the base rufiventris, sp. n.; Mexico. 



Hind femora and tibiae yellow at the tip. 



Antennae yellow sallei, Costa ; Mexico. 



Antennae black rogersi, sp. n.; Costa Rica. 



First joint of the hind tarsi black ; hind femora reddish- 

 yellow cerdo, sp. n. ; Panama. 



Front legs not yellow. 



Wings clouded with brown before the apex fumipennis, Westw.; Brazil. 



femoratus, Karsch; Brazil. 

 Wings not clouded before the apex. [bia. 



Hind legs altogether black (?) columbianw, Karsch; Colom- 



Hind tibia black, except a white dot at the base . . . famoides, Westw.; Mexico. 

 Hind tibiae with the distal third yellowish-white . . lugubris, sp. n.; Mexico. 



