FAMILY HABITS IN BUTTERFLY LARViE THE LIMENITIDS. 37 



of the leaf, parallel to the outer edge all the way to the midrib ; as the 

 bit of leaf thus left unsupported begins to droop, guys are spun from 

 it to the solid leaf on the opposite side of the canal, and to the midrib ; 

 it is then eaten away from the leaf, and the triangular bit remaining 

 falls, hanging by its threads, and swings to the base of the perch, or is 

 pulled there by attaching successively shorter threads. Here it is 

 bound loosely. As other bits are added there comes to be an open 

 packet, held together by simple threads, and of about ^in. in diameter. 

 The packet is moved along as the larva feeds, in the two younger 

 stages, and is always kept close to the leaf, partly by pushing, what is 

 gained at each effort being secured by threads, or it is rolled by attach- 

 ing successive threads from the farther side to the leaf and rib, till the 

 mass is turned over. The packet is not increased after the second 

 stage is passed, and is left behind, the caterpillar no longer frequent- 

 ing the perch constructed in its earlier days, and which has now 

 become too weak for its weight ; it now prefers the footstalk of a leaf or 

 a twig. The same observer further notes that the young larvae of Basi- 

 larchia eros also make little packets of bits of food, which are held together 

 and fixed to the perch, near its base, by silk, and that they push and 

 drag these packets back as the substance of the leaf is eaten. The 

 interest of this to European lepidopterists lies in the statement made 

 by Scudder that " the larva of Najas populi is also described by 

 Dorfmeister (Yerh. zool.-bot. Ges. Wien., iv., pp. 483-6) as making a 

 similar packet of riff-raff to that made by Basilar chia." 



As to its supposed value, Edwards states that he was at first puzzled 

 to account for this construction ; but, happening to see one of the 

 caterpillars back down the perch and drop its excrement directly into 

 the packet, it occurred to him that really this was the magazine whence 

 the larva drew its materials for lengthening the perch. On pulling 

 some of the packets apart a few grains were always found in them. 

 This Edwards believes to be the use of the packets, and he observes 

 that, without some contrivance to catch the frass, it is difficult to see 

 how the larva could obtain the materials it uses. Apparently it drops j ust 

 about enough into the packet for the object in view, for it is certain that 

 the grains are usually expelled wherever the larva happens to be, and fall 

 to the ground. After the end of the perch is sufficiently strengthened 

 and there is no further need of the grains, the packet is dropped behind 

 and neglected. Scudder, on the other hand, thinks that this loose 

 ball, about the size of a small pea, made out of bitten scraps of leaf 

 held together by strands of silk, and attached by a thread to the midrib 

 on which the larva is resting, so that it is moved by every breath of 

 wind, is perhaps a device to distract from itself the attention of an 

 enemy, for, by constant removals, it is always kept close to the eaten 

 edge of the leaf, whilst the position of the larva is as far out on the 

 stripped midrib as it can find a good footing. 



It appears to be a very definite habit in the Limenitids to feed up 

 comparatively rapidly in the spring after hybernation. Dorfmeister 

 notes (Verh. zool.-bot. Ges. Wien., iv., pp. 483-6) a larva of Xajas populi 

 that was in winter-quarters on May 17th, but ate so voraciously and fed 

 up so rapidly that it had pupated by June 5th, and Breyer similarly 

 observes (Ann. Soc. Ent. Belg., v., pp. 62-3) that the larva of Limenitis 

 sibylla is voracious and grows rapidly in the spring, whilst Buckler 

 also states that it loves the sun, and, when it is exposed to it, appears 



