BKITISH BUTTERFLIES. 



upper- or green side of the leaf, which the larva? resemble in colour, 

 being of a dark green, and eating only daring the night and early morn- 

 ing up to about 9 a.m., growing but very slowly and only beingiin. long by 

 the latter part of October. In spring, however, the larva changes to a 

 fine, furry, light green, nearly white, and exactly resembling the 

 underside of the leaves upon which only it feeds. So sluggish is the 

 larva when removed from the plant that it appears to be lifeless, and 

 will remain so for several hours. Buckler says that the young larva of 

 Paunicia phlaeas is sluggish, generally making a little channel on the 

 underside of a leaf just the width of the body, and about its length, 

 so that the larva lies sunk in this channel about on a level with the 

 surface of the leaf, etc. Chapman observes that the habit of the 

 young larva of Rinnicia phlaeas (and others) in changing to a fresh 

 furrow may be very useful by aiding the larvae in being inconspicuous. 

 When the larva is in a furrow that it quite fills, the furrow is practi- 

 cally invisible, the larva supplying the place of the lost tissues of the 

 leaf, but when there is an unoccupied portion behind the larva it shows 

 a white spot either from above or below ; an abandoned furrow is, 

 therefore, fairly conspicuous. It is an instance of what is so frequently 

 observed in other lepidopterous larva?, viz., that, whilst the larva is 

 there, it and its devastations are difficult to see, but are obtrusive as 

 soon as the larva has left. Newman observes that, when full-fed, the 

 larva? rest on the underside of the leaves, closely appressed to the surface, 

 and, when walking, gliding over the surface exactly in the manner 

 of a slug, no separate motion of the body or legs being perceptible. 

 The larva of Clirysophanus dispar also has a snail-like crawl, and ex- 

 hibits, when in motion, a very distinct subspiracular flange, formed of a 

 rather deep longitudinal depression between two outstanding upper and 

 lower elements, the latter of which, on either side, flattens out against the 

 resting-surface, hiding the prolegs and true legs w T hen the larva comes 

 to rest ; when crawling, however, the venter is kept very flat againsb 

 the surface, the motion forward being extremely slow, the larva 

 stretching out its head in an enquiring way when in doubt, etc. 

 Chapman says that the slug-like aspect comes out in several w T ays, e.g., 

 in the absence of dorsal ridges, the close application of the lateral 

 margin or flanges to the surface on which the larva is crawling, etc. 

 He adds that the larva, if one can regard it as not a slug, but as an 

 emerald with a dewy coating or simply as a caterpillar, is really 

 beautiful. Sich says that the larva is able to move its legs and 

 claspers without disturbing the dorsum, so that it seems rather to 

 glide than to walk ; as a matter of fact, it takes very short steps with 

 a continuous motion, and, as all the under-parts are very soft, their move- 

 ment does not affect any usually visible part of the larva unless it is 

 travelling at an unusual rate of speed. If irritated in front, the larva 

 can retreat backwards. 



Prideaux observes (in lilt.) that the young larvae of ChrysopJianus 

 hippotho'e burrow into the soft tissue of the leaves of I turner dcetosa and 

 /«'. acetosella, Leaving behind them a pale track of unconsumed epi- 

 dermis, with traces of adhering frass, but, later, they readily devour 

 tlic entire leaf, with the exception of the base of the midrib and stalk. 

 The black head is unseen during feeding, the collar-like prothorax 

 being pressed against the vdi^c of the leaf. lie further notes 

 (Ent, Hcc, xviii., p. 2-1 0) that the young larva 1 of Loweia aid- 



