58 _ INSECTA. 
riegated colours with which they are adorned, ‘their large wings:re- 
sembling lustrous gauze, and the velocity with which they | pursue the 
Flies, &c., that constitute theirfood, attract our attention and enable 
us to recognize them with facility.. Their head is large, rounded, 
or in the form of a broad triangle. They have two great lateral 
eyes(1) and three simple ones situated on the vertex; two antenne, 
inserted into the forehead behind a vesicular prominence, composed 
of five or ‘six joints, or at least of three, the last of which i is com- ° 
pound and attenuated in the manner of a stylet;°a semi- -circular 
arched labrum; two very strong, dentated and squamous mandibles; 
maxillz terminated by a piece of the same consistence that is den- 
tated, spinous, and ciliated on the inner side, with a uniarticulated 
palpus laid on the back and representing the galea of the Orthop- 
tera; a large, arched, trifoliate labium, of which the two lateral leaf- 
lets are palpi; a sort of epiglottis or vesicular and longitudinal tongue 
in the interior of their mouth; a thick and rounded thoraxs a highly 
elongated abdomen which is sometimes ensiform, and at others re- 
sembles a rod, terminated in the males by two lamellar appendages 
varying in am according to the sii Se and, atic te short legs 
curved forwards. 4 
The under part of the second annulus of the abdomen contains the 
‘sexual organs of the males, and as those of the females are situated 
on the last ring, the coition of these Insects is effected ina different 
manner from that of others. The male, first hovering over his fe- 
male; seizes her by the neck with the hooks that terminate the pos- 
terior extremity of his abdomen, and flits away with her. After a 
shorter or longer period, the latter, yielding to his desires, curves her 
abdomen downwards, and approximates its extremity to the genitals 
‘of the male whose body is then bent into the form of a buckle. This 
junction frequently occurs in the air and sometimes on the bodies 
where they alight. “To lay her eggs the female places herself on 
some aquatic plant that is raised but little above the water, into 
which she plunges the posterior extremity of her abdomen. 
The larve and the chrysalides inhabit the water until the paniaa 
ee 
(1) For their structure, see Cuv., Mém. de la But d’Hist., Nat., de Par., - Ato, 
p- 41. R 
(2) MM. Van der Linden and Toussaint Charpentier have made idee 
study of these appendages. The latter has carefully figured all these varieties 
in his Horw Hntomologice. The genus Petalura; Leach, Zool. Miscel., being 
essentially established on characters drawn from these appendages, appears to 
me to be inadmissible, and for the simple reason, that if this ground of division 
be once received, we shall have to establish almost as many genera as there are 
species. 
