124 



HORTENSE BUTLER. 



ZYGOPTERA. 

 CALOPTERYGID^. 



Calopteryx angustipenuis Selys. 



Calopteryx maculatus . . Beaiiv. 



Cora inca l^elys. 



Diphleliia lestoides Selys. 



Epiophlebia superstes Selys. 



Euphea mason i Selys. 



Hetserina americana Fnbr. 



Mnais st rigata Selys. 



Neurobasis chinensis Linne. 



Thore picta Ramhiir. 



AGRIONID.E. 



Archilestes grandis Selys. 



Argiolestes icteromelas Selys. 



Ceratula capreola Hagen. 



Disparoiieura vittata Selys 



Hemicnemis biliiieata Selys. 



Heteragrion flavovittatum Selys. 



Mecistogaster sp. ? 



Nesolestes alboterniinala Selys. 



Platycneniis aciitipeiniis Selys. 



Protoneura capillaris Rrtmbur 



Pyrrhosonia nymphiila Sulzer. 



Synlestes weyersi Selys. 



Telebasis allaudi Martin. 



Xanthagrion erythroiieunini ■ . . -Selys. 



It will be observed that, with the exception of the Libellulidse, in 

 which the usual parts of the lateral lobe are almost unrecognizable, 

 these adult labia are very similar. The chief differences are in the 

 presence or absence of the cleft in the ligula and in its size and shape 

 when present, in the shape and size of the movable hook and of the 

 hooks on either side of it, and in the presence or absence of the hairs 

 on the whole labium. The general contours are very similar, and 

 the same parts are present in all the groups, the main differences 

 being in the degree of fusion of parts. 



Nymphal Labia. 



In the consineration of the nymphal labia of the various groups, 

 • it will be well to observe the same sequence which was followed in 

 treating of the adult labia. The Libellulidse will therefore first 

 engage our attention. 



L,IBELLrL.ID.C:. 



In this family the nymphal labia are, upon the whole, somewhat 

 more complicated than the adult labia. The mentum has much the 

 same appearance and the ligula is, as a rule,, rounded on its front 

 border, as in the adult ; but the lateral lobe is quite dissimilar. 

 Perithemis domitia (PI. VI, Fig. 5) is typical of the group. The 

 lateral lobes are toothed along the ends, and near the outer edge 

 appears a row of five setse terminated by the strong, spine- like, 

 movable hook. Two groups of nine setse each appear midway 

 down the mentum. l^he lateral lobe of Tetragoneuria cynosura 

 (PI. VI, Fig. 5 h) is very similar, with the exception of the fact 



