HARD WICKE'S SCIENCE- G OSSIP. 



151 



Many of these hairy caterpillars have the power 

 of causing an intolerable urticating sensation when 

 handled, as is well known in the case of the large 

 and handsome larva of the fox moth {Bombyx rubi) 

 which saves them from falling a prey to rooks and 

 other natural enemies. Many larvse find protection 

 in being brightly coloured, because such, as is well 

 known, are highly distasteful to birds. Then, others 

 are provided.with the means of creating a disagree- 

 able odour, ' as, for example, the caterpillar of the 

 swallowtail butterfly [Papilio machaon), which power 

 it employs for the purpose of driving away ichneumon 

 flies and other enemies. For a similar purpose, too, 

 the comical caterpillar of the puss moth (Dicranura 

 vinula) possesses a pair of tail-like appendages which 

 it slashes about over its back when annoyed. Its 

 brilliant colouring, and remarkable power of ejecting 

 a fluid at its^enemies, combined with its formidable 

 appearance, proclaim it to be one of the most highly 

 specialised of Lepidopterous insects. 



The'pupas of Lepidoptera are not less favoured by- 

 nature with means of protection than larvse. Take, 

 for example, the cocoon, of the emperor moth 

 {Saturnia pavonia), which is so wonderfully con- 

 structed that it will allow the imago to escape while 

 ■excluding the possibility of enemies getting in from 

 without. The cocoon of the puss moth {Dicranura 

 vinula) furnishes us with another marvellous example 

 of mimicry. <v It is frequently spun up in some hole 

 or crevice of a tree, and made to fit in so nicely that 

 the depression is filled up level with the surface of 

 the trunk, and the caterpillar, by gnawing and mixing 

 pieces of the bark with its cocoon, makes it minutely 

 resemble the colour of the tree trunk itself. 



The chrysalids of many Rhopalocera, as those of 

 Papilio machaon, Fieri s rapa, Vanessa urticce, etc., 

 are gifted with the power of assuming the colours of 

 objects by which they are surrounded. 



Among the imagines of butterflies and moths 

 numerous examples of mimicry may be obtained. 



Many of the clearwing moths (Sesidae) mimic 

 Hymenopterous insecfs ; for example, the hornet 

 clearwing {Trochilium apiforme) bears a remarkable 

 resemblance to the stinging hornet, which affords it 

 exemption from falling a prey to many birds. 



There are not a great number of Lepidoptera, 

 however, which mimic other animals. The 'great 

 majority find most protection in their resemblance 

 to vegetation and inanimate objects. The Vanessidse, 

 for instance, when at rest with their wings closed, 

 wonderfully resemble the objects (tree trunks, palings, 

 etc.) upon which they settle. 



The Pieridse are highly endowed with protective 

 colouring, the veined wings of these butterflies 

 minutely resembling the leaves of plants upon which 

 they shelter. Gonepteryx rhamni is another butterfly 

 which I have particularly noticed in mimicking the 

 leaves of its pabulum the buckthorn. It has the 

 habit of nesting on the under side of the leaves which 



are of a lighter colour than the upper surface, and 

 which more nearly resemble its own. The tail-like 

 points of its wings represent the apex of the leaves, and 

 in addition the veins of the insect's wings altogether 

 produce an excellent comparison to the leaves of this 

 tree. The little green hair-streak ( Thecla rubi) also 

 minutely resembles the leaves of trees of various 

 kinds. A great number of Lepidoptera resemble 

 dead leaves, as, for example, do all the Hybernidae, or 

 winter moths. 



The lappet moth (Lasiocampa qucrcifolia) looks 

 exactly like a brown oak leaf. 



Many species resemble flowers in appearance, such 

 as Lyccena argiolus, to the flowers of the holly, and 

 Euchlo'i cardamines to the flowers of various umbel- 

 liferous plants. The buff-tip moth {Phalera biccephala) 

 when at rest resembles a piece of stick. Other moths 

 resemble the droppings of birds, such as Melanthia 

 albicillata and M. ocellata, &c. 



Some species resemble splashes of mud and streaks 

 of dirt, while others even resemble the bare ground 

 in colour. The two little butterflies Cccnonympha 

 pamphilus and Polyommatus phlceas, when chased, will 

 often close their wings, fall to the ground, and remain 

 quite motionless, trusting to the concealment afforded 

 by their sombre hues. 



One insect, the pale brindled beauty moth 

 {Phegalia pedaria) I have noticed to closely resemble 

 the lichens and mosses on the trunks of trees with 

 which they are thickly clothed at the time of the year 

 when the insect is most abundant. It is thus very 

 difficult to discern the moth when at rest on the 

 trunk of an oak-tree. It may be observed that this 

 insect, when alive, possesses a beautiful greenish- 

 glossy tinge, which, however, it loses after death. 

 The instinct which prompts moths to rest on or near 

 objects which resemble themselves in colour is really 

 marvellous. 



I have frequently observed, in the case of Bryophila 

 pcrla, a great inclination to rest on blue bricked or 

 stone coloured walls, on account of the resemblance 

 which it bears to them in colour. On the other 

 hand, it avoids red-bricked walls, and will never rest 

 on them whenever it can obtain one of the former 

 colour. If it is compelled through circumstances to rest 

 on red-brick walls, it invariably selects the mortar. 



I have observed a somewhat similar instance with 

 reference to Lobophora viretata, which prefers resting 

 on moss-covered holly-trees to oak-trees, because the 

 former are more thickly clothed with vegetation at 

 the time of the year when it makes its appearance. 



Other species of Lepidoptera seek protection by a 

 variety of other means, some of which we must not 

 forget to notice, as they are exceedingly remarkable. 

 Charaxas graminis and Tapinostolafulva, for instance, 

 will, when disturbed, remain perfectly motionless, 

 and, if touched, will work themselves like a wedge 

 down to the very bottom of the herbage, and thus evade 

 discovery. It is really remarkable what a propensity 



