THE SILK-SPINNING HABIT IN BUTTERFLY LARVJE. 57 



hangs freely in order to change to the pupal state. Some of the most 

 interesting of the puparia spun by butterfly larvae are those of certain 

 Vanessids, Argynnids, and Melitaeids. Among the former, one may 

 note the large open umbrella-like puparium of Pyrameis atalanta, 

 formed by the larva spinning nettle-leaves together, yet quite open 

 beneath, in order to facilitate the escape of the imago. There is also 

 the often almost globular silken puparium spun by the larva of P. 

 cardui, and a somewhat similar one spun low down, near the ground, 

 by the larva of Argynnis aglaia. Many of the Melitaeids, too, spin 

 silken puparia, and the larvae of Melitaea cinxia, when fullfed, do 

 not always lose altogether the gregarious habits of their younger stages. 

 We have noted (Ent. Bee, iv., p. 169) that, on one occasion, three larvae 

 of this species had spun a common silk tent, in which they had changed 

 to pupae. It is quite common to find a number of larvae of this species 

 spun up for pupation in close proximity to each other. Newman says, 

 dozens of chrysalids are often suspended to the plantain almost close 

 to the ground, in company. The larva of M. aurinia pupates alone, 

 spinning a .large quantity of loose, flossy silk, from which it suspends 

 itself for pupation. 



We have already noted (antea, p. 53) on the gregariousness of certain 

 Pierid larvae, and the nests spun by Aporia crataegi, and the Mexican 

 species, Eucheira socialis. A note by Anderson and Spry (Victorian 

 Butterflies, pp. 36-37) on another Pierid, Delias harpalyce, whose larva 

 feeds on a species of mistletoe (Loranthus pendulus), suggests that the web 

 spun by the gregarious larvae of this species is more or less utilised as a 

 basis for the pupation pad. They write : " The larvae, after the second 

 moult, spin a silken footing for themselves wherever they go, and these 

 spinnings, from so many larvae feeding gregariously, form, eventually, 

 quite a web-like habitation, which, no doubt, is of great service in 

 enabling the caterpillars to maintain their footing during high winds 

 or storms. When fullfed, they spin more than ever, and then, 

 attaching themselves to the web, turn into pupae." Floersheim, how- 

 ever, particularly insists (Ent. Bee, xvii., pp. 310-311) that the larval 

 habitations of Pyrameis atalanta are not, as often stated, used as puparia, 

 but that the pupa, as noted above, is attached to the underside of a kind 

 of umbrella, formed by drawing nettle-leaves together, and quite open 

 beneath ; this kind of puparium is what we know. We opened a great 

 number at Val Tournanche in August, 1905, each containing a pupa. 



The belief that the silk-spinning habit of certain larvae is some- 

 times utilised in forming protective homes against adverse weather 

 conditions — particularly of wind and rain — and this not only in the 

 direction of making puparia, but also in earlier larval life, has often 

 been expressed, and it is possible that this idea is well-founded, e.g., 

 the silk-spinning habits of the larvae of Eugonia polychloros are almost 

 identical with those of Euvanessa antiopa, both tree-feeding species, and 

 are apparently entirely different from those of Aglais urticae, Vanessa io, 

 etc., allied species feeding on low plants, the silken habitation made 

 by the larvae of the two first-named species being much more ex- 

 tensive and permanent than in the case of the two last-named. 

 Do these more extensive webs give a greater degree of safety on trees ? 

 Chapman observes that " the young larvae of Eugonia polychloros and 

 Euvanessa antiopa cover their eggs, and the neighbourhood where 

 they were deposited, with a silken web, not spun, as it were, of set 



