44 BRITISH BUTTERFLIES. 



and present a gradual tapering at the anal end, which, by being pressed 

 closely on the resting- surface, adds to the general resemblance the 

 larvae bear to their foodplant when at rest. There can, it seems to us, 

 be no possible doubt that the longitudinal markings of the Satyrid 

 larvae are such as best render them inconspicuous, and consequently 

 offer the greatest amount of protection on foodplants in which an 

 arrangement of parallel lines and parts are the predominating feature. 

 To complete the cryptic resemblance when at rest, some Satyrid larvae 

 have, in addition, horns on the head, which are held out directly in 

 line with the body. Thus Scudder notes (Butts. New .Engl., p. 197) 

 that the head-horns of Satyrodes eurydice are, when the larva is 

 active, inclined forward, their hinder edge forming an angle of about 

 35° with the perpendicular ; when at rest the head is bent beneath the 

 body, so that the hinder edge of the horns lies in a line with the dorsal 

 surface of the body. He adds that he has found that the abdominal 

 horns are always held horizontally, whether the caterpillar is at rest 

 or in motion ; but Edwards says that, when feeding, they are elevated 

 at about 45° and separated. 



In accordance with their specialised colour and markings, fixity of 

 position and immobility are the two main necessities for the absolute 

 perfection of their special mode of cryptic protection. These charac- 

 ters we find developed in a high degree in all Satyrid larvas. The 

 caterpillars remain immovable for a long time in the position of rest 

 they take up ; when disturbed they fall to the ground, and, by almost 

 imperceptible wrigglings, work their way down among the roots of 

 their foodplant, or, if moving from one place to another, do it so 

 slowly and unobtrusively, with a slow gliding movement, that the eye 

 hardly perceives the motion. This, then, is one of the first family 

 features of the Satyrid larvae, viz., the uniformly sluggish character of 

 their movements. This lethargic condition is common to the Nearctic 

 and Palaearctic species, e.g., Scudder notes that the caterpillar of 

 Cercyonis alope is exceedingly lethargic in its action, and, even w 7 hen 

 full grown, moves with exceeding slowness, by almost imperceptible 

 nervous forward twitches. He further observes that, during the earlier 

 stages, the larvae of Satyrodes eurydice are exceedingly quiet, remaining 

 on a single blade of grass, near the tip, from the sides of which they 

 eat long irregular patches, nearly or quite to the midrib, with very 

 slow movements. He quotes Sandberg as observing that the larvae of 

 (Ends bore are very indolent, and when handled shrink and remain 

 long motionless, and adds that this is also true of the larvae of (E. 

 semidea, which are very sluggish, and coil themselves into a half-ring when 

 handled. The larvae of Cissia euryttis, he says, excel in their lethargic 

 habits and slow movements, for, when about to moult, the larvae 

 remain for three or four days, before this event, motionless, and as 

 many after, whilst there are also periods of several days, between the 

 moults, w T hen they rest absolutely, and take no food. They are 

 sluggish at all times, move very little, and with great deliberation . . 

 . . The actual larval movements are exceedingly slow 7 , and almost as 

 difficult to see as the motion of the minute hands of a clock. 



The general feeding-habit of the Satyrid larvae is very uniform, 

 and presents another marked family feature. In the early stadia the 

 larvae usually remain on the foodplant, feeding occasionally both by 

 day and night, but as they get older they feed only at night, retiring 



