140 STATES OF INSECTS. (Larva.) 
way as the Geometers. This even prevails in a few 
where these organs are all of equal length. 
5. Many of the larvee of Tinea L. which live in the 
interior of fruits, seeds, &c. have but one pair of prolegs, 
which is attached to the anal segment. 
6. The larvee of Haworth’s genus Apeda*, remarkable 
for their slug-like shape and appearance, move by the 
aid of two lateral longitudinal pustule-like protuberances, 
which leave a trace of a gummy slime in their course. 
Hymenoptera.—The larvee of the different tribes of 
saw-flies, almost the only Hymenopterous insects in 
- which prolegs are present, have a variable number of 
these organs; some sixteen, as the saw-fly of the willow 
(Cimbex lutea), and this is the most numerous tribe of 
them, including the modern genera, Czmbex, Pteronus, 
&c. Others have fourteen, as that of the cherry (Do- 
lerus ? Cerasi); and many others with only nine joints to 
their antenne. A third class have only twelve, as that 
of the rose {Hylotoma Rose), but this contains but few 
species. ‘The last class contains those that have no 
prolegs at all, but only the six horny ones appended to 
the trunk. Of this tribe, the caterpillars of which have 
a very different aspect from the preceding, are those of 
the genus Lyda (L. erythrocephala)®. Two of the pro- 
legs are anal, and the rest intermediate, and none are 
2 See above, p. 135 note *. 
b De Geer ii. ¢. xl. f. 15, 16. Bergman has added to these four 
classes of the larve of saw-flies, a fifth; the insects belonging to 
which, he affirms, though they have sixteen prolegs, are without the 
anal pair. Ibid. 931. But as neither De Geer ner Reaumur ever met 
with one of this description, it is probable he was mistaken. Reaumur 
thought he had seen one with eighteen prolegs upon Erysimum Alh- 
aria (vy. 91), but he does not speak positively. 
