April 27, 1888,] 



SCIENTIFIC NEW^S. 



397 



Fight Between a Leopard and a Bear. — A curious 

 incident lias just occurred at Darjeeling in connection 

 with a leopard. It was known to be an exceptionally 

 savage beast, and about six weeks ago killed two mules 

 and a pony within half a mile of our garden. The other 

 day my men found a bear which had been killed and 

 half eaten by it. There must have been a tremendous 

 fight, and the animals appear to have rolled together in 

 their struggles fifteen or twenty feet down through the 

 forest. I was not well enough to go out, but lent my 

 gun to a native to sit up in the evening over the remains 

 of the carcase, consisting of the hind legs. The men 

 returned when it got dark, having seen nothing, but 

 during the night the leopard came back and finished 

 off everything except the skin. It measures over five 

 feet, not a very big one, but quite up to the average, and 

 a real black bear. 



The Life of an Eel. — M. Desmarest gives in the 

 Naluraliste (reproduced thence in Humboldt) an account 

 of an eel which lived in his family from 1829 to 1869. 

 Its life was passed under unfavourable circumstances. It 

 was kept in an earthen pan, in which it had to lie coiled 

 up, the water being changed twice weekly. Since 1852 

 it was placed in summer in a roomy zinc tank, but was 

 returned to the earthen pan in winter. Twice it was 

 completely frozen up, in the winters of 1851-1852 and 

 again in 1864, but sustained no injury. It was fed with 

 small bits of meat, but only in the summer. The fish 

 seemed to know its keepers, and raised its head slightly 

 up out of the water if it wanted food, or if it was called. 

 In the summer of i86g, during very hot weather, it con- 

 trived to escape from its tank, and was so scorched by the 

 sun that it perished. In spite of its age, its weight was 

 only about 2 lbs. 3 ozs. 



Spring Flowers. — Dr. J. E. Taylor, referring to the 

 fact that these plants have a tendency to flower before 

 they come in leaf, suggests that this early flower- 

 ing tendency is a survival of a habit which the plants 

 formerly had to blossom under more vigorous conditions 

 of climate. He thinks that our spring flora has survived 

 through its ability to bloom at an early period of the 

 year at low levels, while flowering later at higher alti- 

 tudes. 



Appearance of the Swallow. — The first sv\'allow of 

 the season, says La Nature, was seen on March 30th, near 

 the Font Neuf. 



SCALE INSECTS. 



IF we look carefully at the plants in a greenhouse, we 

 shall very likely see here and there upon the leaves 

 or branches a little cottony tuft, too minute to attract the 

 attention of an incurious eye. With a needle or sharp 

 penknife the mass may be scraped off, and put upon a 

 slip of glass. If we add a large drop of absolute alcohol, 

 the cottony threads become indistinct, and soon dis- 

 appear. This at once proves that they are not really 

 cotton, nor indeed hairs of any kind. Before the fluid 

 has time to evaporate, we may lay a cover glass upon 

 it, and examine under a microscope. If the specimen be 

 taken during the early months of the year, we shall see 

 a great number of very small insects — six-legged, without 

 wings, not very unlike cockroaches, but say ten thousand 

 times as small. They are the larvae of a scale insect. 

 White, in the " Natural History of Selborne " 



(Letter 97), describes carefully a similar insect which 

 infests the vine. He speaks of husky shells enclosing a 

 cotton-like substance, in which multitudes of eggs were 

 entangled, and quotes a correspondent who tells of a 

 vine suddenly overspread by large lumps of a clammy 

 fibrous substance, resembling spiders' webs or rather 

 raw cotton. It was pulled off by handfuls, but could 

 not be cleared away. The grapes never filled to their 

 natural perfection, but turned watery and vapid. 



Scale insects are too familiar to the gardener to excite 

 his interest. If you talk to him about their habits, it 

 may be that he will lose temper, and the most sympa- 

 thetic remark which you can expect will relate to some 

 method of destroying them. To the naturalist, however, 

 these insects are a most curious study. Their mode of 

 life, and the light which they throw upon other insects of 

 great economic importance, justify a careful examination. 



The scale insects are distantly related to the greenfly 

 or aphis, also a pest in its way, and more closely to the 

 phylloxera of the vine. This does not in the least 

 redeem their character. It is perhaps more to the point 

 to say that they are first cousins of the cochineal insect, 

 the lac insect, the wax insect, and the kermes — creatures 

 of commercial and historical interest. Kermes yields 

 the principal scarlet and crimson dyes of the ancients — 

 the scarlet and crimson of the Old Testament. The lac 

 insect provides us with shellac, and also with a red dye 

 much used in eastern countries. Cochineal is still of 

 great commercial value, and until azo scarlets had been 

 extracted from coal-tar, it held the first place among red 

 dyes. Carmine is a preparation of cochineal. 



In all these insects the mode of life is generally similar. 

 The larva escapes from the egg, feeds and grows, gaining 

 the shelter which it needs either beneath the body of 

 its mother or among the cottony tufts which she has 

 prepared. In the warm season it runs about for a short 

 time over the tree, chooses for itself a convenient 

 lodging, and then thrusts its proboscis into the bark. 

 After this, in many cases, it moves no more. It feeds 

 upon the juices of the tree, and produces its eggs on the 

 same spot where it has lived during a great part of its 

 own life. Sometimes it becomes as it were inflated into 

 a balloon, lodging its young ones apparently within, but 

 really beneath its body. This is the case with the 

 kermes. Other scale insects, like that so common in 

 greenhouses, exude from their bodies the cottony fila- 

 ments which serve as a nest for the young. The male 

 is a rover. He has no proboscis, never settles, and never 

 feeds, but he has a pair of large gauzy wings, which 

 enable him to pay his court to the sedentary female. 



We have seen that the cottony threads dissolve in 

 alcohol. They are really filaments of wax, squeezed 

 out from pores in the body of the female, by a process 

 not unlike the exudation of wax in a bee. A few scale- 

 insects, such as the wax insect of China, shape these 

 waxy filaments into cells, within which their larvae dwell 

 comfortably. Whether the wax is of animal or of vege- 

 table origin may be a question. Many plants produce it 

 in abundance, as a delicate bloom upon the leaves or 

 fruit. The wax palm even secretes it in quantities which 

 are commercially available. These facts suggest that 

 the scale insect merely appropriates a substance ready- 

 made in the sap of the tree. On the other side we have 

 the experiments of Dumas and Milne-Edwards, which 

 tell us that bees, fed upon pure sugar, were nevertheless 

 able to continue the secretion of wax. 



Several scale insects, among which the chief are 



