NEUROPTERA. — EPHEMERID&. 31 
is produced into the long curved horn above described. The max- 
ille (fig.61.10.) are small, membranous, curved, pointed at the tip, 
and internally setose ; the maxillary palpi do not extend beyond the 
front of the head; they are 4-jointed, the basal joint being very 
short; the lower lip (fig. 61.11.) is very large and membranous, co- 
vering the underside of the mouth; it is quadrilobed (jfg.61. 12.), 
and furnished within with a broad tongue (fig. 61. 13.), of which 
the anterior angles are produced and pilose ; the labial palpi are 
broad and 3-jointed; the antenne are about twice the length of the 
head, multiarticulate, and ciliated ; the eyes are large and rounded ; 
the legs are short, broad, and very much compressed ; the tarsi 
2-jointed, with a terminal hook (fig.61.14.); the abdomen is 9-jointed, 
the terminal segments being the longest: of these segments, the 
six basal ones are furnished on each side with a pair of elongated 
rather narrow gills, the edges of which are furnished with long, nar- 
row filaments (jig 61.15.), through each of which an air-tube ex- 
tends to the tip; the air-tubes from each contiguous pair of filaments 
uniting near the base, and then running to the large tube which tra- 
verses the centre of each gill. Each of these pairs of gills are united 
together at the base, so that in the whole the insect has twenty-four 
gills. The insect, of which the history is figured by Schaffer (Abhandl. 
vol. iii. pl. 1.), appears to be an Ephemera, with four wings, and three 
tails, the larva of which forms burrows in the earth; but it is impos- 
sible, from his figures, to ascertain either the species or the real cha- 
racters of the preparatory states. 
In a small species figured by De Geer (Mém. tom. ii. tab. 17. 
f.11—16), having four wings and three tails, the eyes of the male 
being very large and much elevated, and which is regarded as the 
E. vespertina (which Mr. Stephens introduces into his second section 
of the genus Ephemera), the head of the pupa is unarmed; the an- 
tenne longer; the legs and anal sete longer and more slender ; the 
seven basal abdominal segments are furnished on each side with a pair 
of oval, flat, membranous gills, each terminating in a long point, and 
not provided with long marginal filaments (fig. 61.19.). The insect 
figured by Résel (Ins. Belust. tom. ii. tab. 12. f 1, 2.) is evidently iden- 
tical, in the structure of the pupa and imago, with these figures of De 
Geer. This and the allied species may, perhaps, from the consider- 
ation of the variation of their preparatory states, be advantageously 
separated as a distinct genus, to which the name of Leptophlebia may 
