558 MODERN CLASSIFICATION OF INSECTS. 
attaches itself by a glutinous secretion to the leaves or stems of 
plants, its body then contracts and hardens (fig. 131. 1.), and the 
insect assumes the pupa state within the larva skin. De Geer (Mém. 
tom. vi. tab. 6.) figures the transformation of Syrphus Ribesii and 
Pyrastri, the larva of the latter of which is much more transversely 
wrinkled than the former. In pl. 7. he has figured the transformations 
of another species, the larva of which is armed with transverse rows of 
strong spines. See also Réaumur’s memoir on the enemies of the 
Aphides (Mém. tom. iii. and pl. 30, 31.), in which he has illustrated 
several species. Bouché has figured the larvee and pupz of Syrphus bal- 
Fig. 131. 

teatus and teeniatus (Naturg.tom.v. fig. 1—6.); other species have been 
illustrated by Rosel (Ins. Belust. Muse. tab. 6.), and Schiffer (Aéd- 
handl. vol. iii. tab. 13.), Albin (Ins. pl. 63. and 66.), Swammerdam 
(Book of Nature, tab. 45. fig. 26—30.), Vallot in Annales Soc. Ent. 
France, 1834, p. 65. App. (S. balteatus and Pyrastri). The larva of 
Ceria Conopsoides, observed by Van Roser ( Verz. Wurtemb. Dipt. 
p- 9.), resembles that of Syrphus. 
The larvee (fig. 131. 4.) of the genus Volucella, above mentioned, 
are also insectivorous, but reside in the nests of Bombi and Vespe, 
upon the larve of which they subsist ; they have the body long, nar- 
rowed in front, transversely wrinkled, with fine lateral points, and the 
tail armed with six radiating points; the mouth is armed with two 
bifid mandibles, and with three pair of tentacula. The pupe of this 
genus have not been described, De Geer figuring only the larva and 
imago of V. bombylans (Mém. tom. vi. tab. 8. fig. 4—9.; and see 
Réaumur, Mém. tom. iv. pl. 33.). All the species are not, however, 
insectivorous, some feeding upon vegetable matter, and being either 
terrestrial or aquatic. Amongst the former are the species of Mi- 
