THE 
IMMATURE STATE OF THE ODONATA. 
PART Il.—SUBFAMILY -AUSCHNINA. 
ZSCHNINA. 
Bopy 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 which the length is the greatest. The form of head, mostly 
square, depends upon situation and form of eyes. 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 Aschna ;— 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 has generally 
indications of ocelli. The anterior portion is cut straight im 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 antenne. Antenne 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 only six-jointed antenne ; 
the last joint the longest. In the La Guayra specimen the antennx are 
abnormal, being only five-jointed. Occiput rather flat, shorter 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 
