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larva does when crawling. In many cases the thoracic legs are altogether 
absent, and their place is taken by fleshy discs ( Nepticula, etc.). The 
ventral claspers, are usually all ill-developed, and often entirely absent 
on the 6th abdominal segment. [Gracilaria, Lithocolletis, Coleophora 
(part)]. The anal claspers are generally better developed. In certain 
genera there are neither legs nor claspers, but in these cases the larva 
is furnished with cone-like processes on certain segments ( Kriocrania , 
Phi/llocnistis, etc.). The larva comprised in sections A and B, which 
do not spend all the feeding stadia in one mine, are well provided with 
legs, most of them are rapid in their movements. The caterpillars in 
section C, which only leave the mine to pupate, are often ill-provided 
with organs of locomotion, and therefore progress in a more leisurely 
manner. They spin ladders of silk, on which they crawl. For instance, 
if we watch a Nepticulid larva leave the mine to spin up, we shall see 
that its head sways from side to side, and as it does so the spinneret 
leaves a strand of silk behind it. On this the larva has a firm hold. 
In the larvae of Nepticula that I have examined, and also in those of 
Phyllocnistis, there are, in the last instar, neither legs nor fleshy discs 
in the prothorax, while both meso- and metathorax carry fleshy discs. 
As the prothorax sways to a certain extent with the head, while the 
larva is spining, and also of course, previously, while the larva was 
feeding in mine (as the true leaf-miner feeds with a side to side motion), 
legs on the prothorax would be more of a hindrance than an advantage, 
the head having greater freedom of movement when the prothorax is 
also free. Hence, I believe the reason for the curious absence of organs 
of locomotion on the prothorax of these larvae. 
There is one curious phenomenon connected with the leaf-miners, 
and which, perhaps, lends itself to very wide suggestion. It has been 
noticed, more especially by Stainton and Wood, that though a leaf 
occupied by a miner may fall from the tree, and even turn browm, yet 
the area affected by the miner will remain green, and to all appearance 
healthy, for a very long time after the leaf has fallen. It has been 
suggested that the larva, even when commencing its mine, in some 
way impregnates the area surrounding it with some preservative or 
antisceptic. I would go one step further, and suggest that all those 
species, Macro- as well as Micro-lepidoptera, which pupate in spun ox- 
earthy cocoons (nearly always lined with silk), impregnate the atmos¬ 
phere of the cocoon with some kind of preservative. 
Generally speaking the leaf-miners are of .very small size. De 
Geer says {Mew., vol. i., men., xiv., p. 481), after mentioning the leaf- 
rollers {Tortrieids), “other larvae still smaller have also need to be 
covered in order to live at their ease,” and adds, “ the moths are 
difficult to find, ‘ a cause de leur peu de volume.’ ” Stainton says of 
Nepticula microtheriella {In. Brit., p. 302), that upwards of thirty larvae 
may be found in a single nut leaf, and Frey preserved a nut leaf in 
which be counted 22 mines of the same species. (Frey Tin. and Pter., 
p. 386.) Being so minute these creatures would speedily perish unless 
protected from drought and from their living enemies. Very small 
larvae would dry up if not protected in some manner, unless they 
always lived in damp situations, and, in that case, the area of their 
activity would be too much restricted. For instance, the genus 
Micropteryx {calthella, etc.), can never inhabit any but wet areas. But 
Kriocrania {purpurella, etc.), a widely separated genus, but still of old 
