532 



SCIENTIFIC NEWS. 



[Nov. 23, 1888. 



which inhabits flowers in California. This creature 

 spins no web, but catches its prey by surprise. In the 

 region which it frequents, a yellow composite flower, of 

 exactly the same shade as the spider, is very common. 

 The creature accordingly takes up its position in the 

 middle of the flower, where its legs are confounded with 

 the anthers. If, as it frequently happens, a fly or a 

 butterfly alights on the flower, it is at once seized and 

 devoured. At the same time the spider escapes the 

 no'ice of passing birds. On leaves, tree-trunks, or on a 

 flower of any other colour this spider would be at once 

 seen and avoided by his prey or seized by its enemies. 

 There is a gaily coloured mantis in Assam and Burma 

 which by the attitudes it assumes deceives butterflies 

 into paying it a visit. The moment they alight on the 

 supposed flower they find themselves in the grasp of 

 their enemy. 



No less formidable a creature than the Bengal tiger, 

 conspicuous as he looks on open ground, is, on account 

 of his vertical stripes, very hard to distinguish among 

 the stems of reeds, bamboos, and other jungle plants. 

 The markings of the leopard, which lurks amidst the 

 foliage of trees, are equally adapted for concealment. 

 Every one must have observed that when the sun is 

 shining through the head of a tree the shadow presents 

 the appearance of rounded spots, dark and light inter- 

 mingled. Thus among the foliage of a tree any animal 

 with eye-like spots, such as the leopard or the jaguar, is 

 not readily detected. 



The tiger, in addition to the jungle-pattern of his skin, 

 if we may so call it, has another method of deceiving his 

 intended prey. He can imitate the whistle of the sambur 

 deer with great nicety, and thus sometimes entices these 

 animals to come unsuspectingly within the reach of his 

 spring. The leopard allures a smaller species of deer in 

 a similar manner. But the most numerous cases of 

 mimicry hitherto placed on record are defensive, not 

 offensive. The species in question simulate the colours, 

 the shape, or the movements of some much more 

 formidable creature, and thus escape attack. 



The pretty beetle, Clytus arietis, not uncommon on old 

 posts and rails in some districts, is very generally taken 

 for a wasp by the non-entomological public, on account 

 of its black and yellow livery. As if aware of its advan- 

 tage, it does not seek concealment. On the contrary, 

 Callidium violaceam, an insect very similar in habits, 

 size, and means of defence, but not mimetic, is exceed- 

 ingly shy, and on the approach of an observer quietly 

 disappears around a gate-post or underneath a rail. 



An admirable case of mimicry is afforded by the cater- 

 pillar of the " lobster moth," Stauropus fagi. From 

 whatever side this larva is viewed, it has a most uncanny 

 appearance. Four of the anterior legs nre very long, 

 and closely resemble those of a spider. If an ichneumon 

 approaches these legs are turned towards her, and moved 

 in a manner like those of a spider when about to seize 

 its victim. The ichneumon having a wholesome dread 

 of spiders, declines the offered embrace, and flits away 

 to find a safer subject into which to insert its egg, and 

 the caterpillar has saved its life by a clever fraud. 



But perhaps in the most numerous cases an insect 

 finds its advantage in mimicking a leaf, dead or living, a 

 turf of moss, a twig, a splash of mud, or the droppings 

 of a bird. One of the commonest of these imitations 

 is shown in fig. 1, which we owk to the courtesy of our 

 contemporary La Nature. 

 The caterpillar^ of th,e moths belopgjng to the numerous 



tribe Geometra (loopers, or spanners) attach themselves 

 by their hindmost pair of feet to the branch of a tree, and 

 remain sometimes for hours in an erect position, very 

 closely resembling a dead twig. 



Our figure represents caterpillars of Uropteryx sambu- 

 caria, a very common species, known to lovers of moths 

 as the " swallow-tail " in such attitudes. 



Other species display a remarkable likeness to leaves, 

 and be it noted, of the leaves of the trees which they 

 feed upon or frequent. Thus the brimstone butterfly 

 (Gonepteryx rhamni), when at rest on a buckthorn bush 

 shows a considerable resemblance to the leaves of that 

 shrub. The lappot moth (Lasiocampa quercifolia) when 

 at rest may readily be confounded with a tuft of sere 

 leaves. Even the most gaily coloured butterflies when at 

 rest often remain unseen. The upper surfaces of the 

 wings are hidden by being brought together in an up- 

 right position over the insect's back, and it often heels 

 over at a small angle to the horizon, so as to present a 

 less prominent appearance. 



Not a few moths contrive to render themselves prac- 

 tically invisible by taking up such a position, e.g., on a 

 papered wall, that their outline may coincide with some 

 line in the design. 



There are beetles, especially of the families Rhyncophori 

 and Chrysomelida, which, without very close examination, 

 cannot be distinguished from a crushed berry or the 

 droppings of a bird. Mr. H. Drummond, in his "Tropical 

 Africa," gives an amusing account of his mystification at 

 seeing a white splash on a boulder suddenly, but slowly, 

 begin to move, and how he could scarcely believe his 

 own eyes until he had turned the insect over and 

 detected a head, six legs, and a segmented body. 



We, along with not a few naturalists of much higher 

 standing, have occasionally been deluded into picking up 

 some little bit of refuse in the belief that it was an 

 insect. 



It will probably be found that instances of mimicry are 

 far more numerous that we are yet aware, and that each 

 has its lesson awaiting the patient inquirer. 



But there are evidently some animals, especially insects, 

 unprovided with any arms, offensive or defensive, and 

 not protected by any form of mimicry. But such species, 

 we suspect, are preserved from extirpation by their 

 wonderful fecundity. Accordingly, though the individual 

 falls a victim by myriads to birds, spiders, and carnivor- 

 ous insects the type survives. 



Mimicry is a fine subject for the young naturalist to 

 study, especially if he has the good fortune to take up his 

 abode in a country but sparingly explored. 



The Tsetse. — M. Channon, writing to Cosmos, desires 

 to mention facts concerning this dreaded insect which may 

 have a certain interest. " In a journey which I recently 

 made to Zanzibar I had to suffer much from this incon- 

 venient Dipteron. (How many Diptera are other than 

 inconvenient ?) I had to traverse a great plain which ex- 

 tends between the mountain mass of Oukami and that 

 of Ngouron. This plain is dry, barren, and uninhabited, 

 but herds of beasts abound, buffaloes, zebras, giraffes, 

 antelopes of all sorts, and even some elephants have been 

 seen. In all this desert as soon as the sun touched the 

 horizon the Tsetse gave me no rest. It is a truly pro- 

 voking beast, but to many it is nothing further. Still, I 

 must remark that after these attacks (I have been bitten 

 more than 200 times) I had to suffer from an affection 

 like nettle-rash, which lasted top. At the places where I 



