532 MODERN CLASSIFICATION OF INSECTS. 
rotten wood. They all, however, agree in retaining the larva skin 
nearly in its original form during their existence in the pupa state. 
The larva ( fig. 127. 4.) of Stratiomys chameleon (first figured by 
Swammerdam, Book of Nature, pl. 39, 40, 41.; Sparrman, in Swed. 
Trans. 1804; Schrank, in Der Naturforscher, st. 27.; Geoffroy, vol. il. 
pl. 17.; Frisch, Beschr. vol.i. pt. 5. pl. 10.) is of an elongated form, 
without feet, depressed and attenuated at each extremity of the body, 
especially the posterior, in which the segments are greatly elongated ; 
the head is small, corneous*, pointed in front ; and the mouth is fur- 
nished with two hooks, four small points, and two palpi, dilated at the 
tips, and clothed with recurved hairs; these organs are kept in con- 
tinual motion, so as to form a constant current, whereby small ani- 
malculz (which are supposed to be the food of the insect) are brought 
to the mouth; the extremity of the body is furnished with a spiracle, 
surrounded by a great number of bearded hairs, which form a coronet, 
and which are capable of being closed up so as to retain a bubble of 
air, and by the assistance of which the insect suspends itself at the 
surface of the water for expiration. On assuming the pupa state, the 
insect floats at liberty in the water, the enclosed pupa (fig. 127. 5.) 
occupying only the anterior portion of its larva skin.+ 
Réaumur (Mém., tom. iv. pl. 25.) has figured the transformations of 
Odontomyia ornata, which closely resemble those of Stratiomys, as 
does also those of Odontomyia hydroleon, figured by De Geer (Mém. 
tom. vi. pl. 9. f. 4.) 
The larva of Vappo (Pachygaster) ater (fig. 127. 9.), described by 
Macquart (Dipt. du Nord de France), are elongated, depressed, 11- 
jointed, each joint having an elongated lateral seta; the head is coni- 
cal, obtuse, and much narrower than the rest of the body ; the parts 
of the mouth appear very rudimental, and are almost obliterated ; the 
last segment of the body is large, black, and semicircular. These 
larve were discovered by M. Carcel in the rotten detritus of the elm 
(Eine. Méth. tom.x. p.779.). M. Schilling has figured this larva 
* Latreille (Regn. Anim. tom. v. p. 485.) describes it as “ écailleuse,” although 
in p. 478. he had described it as “ molle, de forme variable ;” thus erroneously esta- 
blishing its similarity to the Athericera. 
+ It is probably on this account that Knoch (Neue Beitrage, 1801, p. 193.) 
and Meigen (Zw. Ins. vol. iii. p. 133.) entertained the opinion that authors had 
erred in their descriptions of the larva of Stratiomys, considering that the real larvae 
of those insects were parasites within the bodies of the larvee described as the true 
larvee of Stratiomys! ! 
