THE 



IMMATURE STATE OF THE ODOXATA. 



PART II. — Subfamily ^scHxmA. 



.ffiSCHNINA. 



Body elongated. Length from three to six times the breadth. Gills in 

 the end of abdomen. Head large, breadth greater than length, except in 

 Gynacantha, in wliicli the length is the greatest. The form of head, mostly 

 square, depends upon situation and form of ej^es. Eyes always large and 

 produced at inner hind angles in triangular lobe, separated from each other 

 by advanced portion of occiput, which is generally raised and cut square at 

 front border. The eyes vary in prominence, being least prominent in Gyna- 

 cantha, more so in Anax, and most prominent in ^schna; — the line behind 

 the eyes is sometimes straight, sometimes oblique, and sometimes curved. 

 Vertex divided into two parts more or less well defined ; the posterior por- 

 tion is generally more nearly square than the anterior, and lias generally 

 indications of ocelli. The anterior portion is cut straight in front, and is 

 generally somewhat semicircular ; both portions are about on the level of 

 the eyes. On each side of the vertex is an elongated polished spot, in 

 front of which are inserted the antennfe. Antennaj short, slender, and with 

 two exceptions seven-jointed. The two basal joints are globular, stouter than 

 the others; the third, the longest, generally longer than the two basals 

 taken together ; fourth usually shortest ; following joints longer. In Gyna- 

 cantha the sixth joint is the longest. E. Heros has onl}' six-jointed antennae ; 

 the last joint the longest. In the La Guayra specimen the antennae are 

 abnormal, being only five-jointed. Occiput rather flat, .«horter in Brachytron 

 than in the other described species ; sides more or less oblique, sometimes 

 nearly straight ; hind angles more or less rounded ; in Gynacantha forming a 

 sharp angle ; hind border more or less notched, approaching in some species 

 a straight line. That part of the head which lies before the eyes forms a 



