230 NORTH AMEKICAX DIPTERA 



101. Second antennal segment produced thumb-like into the third on the 



inner side (35, 54) Parasyntormon Wheeler 



Second antennal segment transverse or only gently convex apically. . .102 



102. Middle of propleura wholly bare 103 



Middle of propleura with a single bristly hair (64) Leucostola Loew 



103. Lower section of the face not differentiated, the face short 104 



Lower section of the face strongly differentiated, the face reaching 



practically to the lower level of the eyes (45, 81). 



Paraphrosylus Becker 



104. Diaphorus Meigen and Chrysotus Meigen come here but there are no 



good characters for the separation of the females. 



105. Second antennal segment produced thumb-like into the third on the 



inner side (32, 50, 69) Neosyntormon, n. g. 



Second antennal segment with the apex at most a little convex on the 

 inner side 106 



106. Middle of propleura bare 107 



Middle of propleura haired 109 



107. Abdomen flattened dorsoventrally, rai-ely swollen; face narrowest in 



the middle (2>- Campsicnemus Walker 



Abdomen cylindrical or tapering 108 



108. Abdomen short and tapering 110 



Abdomen long and slender, usually cylindrical or laterally compressed 



(42, 53) Sympycnus Loew 



109. Third and fourth veins parallel or nearly so beyond the posterior 



crossvein (10) Keirosoma Van Duzee 



Third and fourth veins rather approximate apically (12). 



Nematoproctus Loew 



110. Scutellum with a secondary pair of weak marginal scutellars situated 



between the base and the strong pair; sixth vein strongly ileveloped; 



anal lobe distinct (8, 33) Peloropeodes Wheeler 



Scutellum without secondary basals, but with a pair of apical hairs; 

 sixth vein weakly developed; anal lobe very weak. . .Teuchophorus Lcew 



Laxina, new genus 



This genus is erected for those species, formerly placed in Con- 

 dylostylus, Sciapus and Psilopns, in which the lower section of the face 

 is hairy. The arista is dorsal; mesonotiim rather square; scutellum 

 with four bristles and the wings either hyaline or variegated with 

 brown. Genotype: — DoUcJwpus patihulatus Say. 



Neosyntormon, new genus 



Differs from Parasijntonnon Wheeler in having the arista dorsal, 

 even though situated toward the apex of the third antennal segment. 

 The propleura is bare and the hypopleura lacks hair. Both these char- 



