132 STATES OF INSECTS. (Larva.) 
be said to have real legs, unless we are to regard as such 
certain tentacula formed upon a different model from 
the legs of other larvee*. Réosel has, I think, figured a 
Lepidopterous apode. No Neuropterous one has yet 
been discovered. 
The legs of larvee are of two kinds; either horny and 
composed of joints, or fleshy and without joints®. The 
first of these, as I observed in a former letter‘, are the 
principal instruments of locomotion, and the last are to 
be regarded chiefly as props and stays by which the ani- 
mal keeps its long body from trailing, or by which it 
takes hold of surfaces; while the other legs, or where 
there are none, the annuli of its body, regulate its mo- 
tions. The former have been commonly called true legs 
(pedes veri), because they are persistent, being found in 
the perfect insect as well as in the larva; and the latter 
spurious legs (pedes spurii), because they are caducous, 
being found in the larva only. Instead of these not very 
appropriate names, I shall employ for the former the 
simple term legs, and for the latter prolegs (propedes)4. 
The legs, when present, are always in number sz, and 
attached by pairs to the underside of the three first seg- 
ments of the trunk. They are of a horny substance, and 
consist usually of the same parts as those of the perfect 
insect; namely, coxa, trochanter, femur, tibia, and tarsus, 
suspended to each other by membranous ligaments: these 
2 De Geer iv. 5. Legs of this kind are figured PLare XXIII. 
Fic. 7. 
> In the larva, however, of Sialis, or some kindred genus, in which, 
like those of Scolopendra, the prolegs are jointed, a pair distinguishes 
each abdominal segment. See Reaum. iv. ¢. xv. f.1, 2. Compare De 
Geer ii. ¢. xxiii. f. 11. 
© See above, Vor. II. 286—. * Ibid. 288. 
> fe ee 
