MAN II IKS \M> Mllti.'KS (!' NKW YolIK -" 



// Tn (ho hind wing the subcostal vein terminates in tin- 

 cost :i at hardly more than half tin- length of the 

 wing, just he\ OIK! tlio obtuse aiigulalion li:i\mir a 

 thickened margin : forceps of male more or less His 



tiiirtly four-jointed Choroterpes 



//// Vein M, and the bisector of the cubital fork both tending 

 to attach themselves to the posterior branch of their 

 respective forks; between the latter and vein 'u. 

 are -enerally some short inlercalaries (the cubital 

 region thus being better developed than in group // i ; 

 caudal setae about as long as the body; penulti- 

 mate segment of the male forceps longer than the 

 antepenultimate 



/ Veins Cu : and 1st A separate to base. .Ephmerella 

 7i Veins Cu, and 1st .4. fused toward the base 



D r u n e 1 1 a geu. nov. 



gg Hind wings absent C a e n i s 



ff The intercalates between the first and second anal veins repre- 

 sented by a series of veinlets, often sinuous or forking, 

 extending directly from the first anal to the wing margin ; 

 costal angulation of hind wing close to the base; but two 

 well-developed caudal setae, the median one being rudi- 

 mentary or wanting; basal joint of hind tarsi evident but 

 not well developed 



// Median caudal seta, a distinctly segmented rudiment (pl.6, 

 fig.l); forceps of male three-jointed; posterior pro- 

 longation of sternum of ninth segment of abdomen of 

 female bifid at tip 



// 1'asal segment of fore tarsus of male shortest; claws of 

 each tarsus unlike each to each; hind wing with the 

 costal angulation acute, and the fork of the median 

 vein occupying two thirds the length of that vein 



C o 1 o b u r 1 1 s 



lih Basal segment of fore tarsus of the male longest; claws 

 of each tarsus alike; hind wing with the costal angula- 

 tion obtuse, and the median vein forked through one 



third it? length C h i r o t e n e t e s 



<jij Median caudal seta more rudimentary or wanting; forceps 

 of the male distinctly four-jointed; posterior prolonga- 

 tion of the sternum of the ninth abdominal segment in 

 the female entire at tip 

 h Claws of each tarsus alike: caudal setae at least one 



half longer than the body Siphlurus 



lili Claws of each tarsus unlike; caudal setae about as 



long as the body in both sexes Ameletus 



Median vein apparently simple, its posterior fork (M 3 ) being 

 detached and appearing as an intercalary; hind wings when 

 present at least twice as long as wide, and provided with 

 but 1-3 longitudinal veins 



