2. 3816 12s. 3 d. 3. £4377 8s. Iod. D. I. £672 15s. 2. 4239-1277. E. 1. 2306 13s. 8d. 2. £8517 25. old. 3. 2,061,108 twopences. F. I. 4,860,734 farthings. 2. £3973 8s. 3. 2477-110. SOLUTIONS OF THE 'ADVANCED EXAMINATION' QUESTIONS IN THE SCHOLAR,' FOR AUGUST, 1882. STANDARD III. 1. 1d. × 200 × 71 × 24=45,000d. = £187 10s. Ans. 2. sov. 1201., and 6× 120=720, no. of pears bought. 720÷90=8 pears each. Ans. £ S. d. 3. 701,723 14 8 60,914 18 93 640,808 15 10%=615 176,443f. Ans. STANDARD IV. 1. £600+ £150= £750, selling price of the tea £750÷2 d. 36,000 oz. 4500 lbs. 2 ton zo lbs. Ans. 2. 25s.2015. 3d., value of one pigeon. Is. 3. x 8=ros., value of 8 pigeons or of 6 rabbits. Is. 8d. or 201.x 300=6000d. = £25 Ans. 3. 36 yd. 3 qr. 3 nl. = 591 nls., × 64 = 37,824 nls., total length. And 6 yd. 2 qr. 2 nl. = 106 nls., required for one dress. Hence 37,824 106=356 dresses and 88 nls., or 5 yds. left. Ans. I. STANDARD V. £ s. d. O Is 8d. x 240 × 50=1025 2. (6s+45.10s.) × 20=10, and 4s. × 40= £8, total £18, excess that the men and women in the aggregate receive over a boy's share each. Then £163-18= £150, which, divided by 120, the number of recipients = £1_5s. Ans. 3. Bringing both the areas to half-roods, and, working by simple proportion, we have £2170 15. x 1206 STANDARD VI. 1. A and B do 12 of the work in a day, and A, B, and C do &part done by C in a day, hence 228+5= 45 days. Ans. STANDARD VII. 1. 20+24+26=70 per cent. in first three classes, hence 30 per cent. must be in the fourth class; but there are 45 scholars in this class, hence 45÷ 30=14, one per cent. of the scholars, and 1 × 100=150. Ans. 2. £3×45=£135 yearly interest before transfer. £925×45=64162'5, amount received on selling out. 3. 6 ac. 2 r. 20 p.=32,065 sq. yds., the sq. root of which= 179 067+yards. Ans. Practical Lessons on Insect Life. BY THEODORE WOOD, M.E.S., Joint Author of 'The Field Naturalist's Handbook.' NO. XIV. THE HETEROPTERA. HE Heteroptera, or, according to some systems, the Hemiptera-Heteroptera, differ from the Homoptera chiefly in the structure of the wings, which, in those species that possess them, are of two different textures, the basal portion of each being hard and leathery, while the remainder is membranous and semi-transparent. Hence is derived the title of Heteroptera, which signifies 'different-winged.' In the Heteroptera, the wings slightly overlap when the insect is at rest, instead of running parallel to one another at the suture, as is the case with the Homop tera. Amongst the other distinguishing features of the group, we may mention the form of the body, which is flattened, and not convex, and also the position of the proboscis, which starts from the front of the under surface of the head, instead of from the back. In many of the Heteroptera the wings are scarcely visible, being, indeed, nothing more than mere rudiments of those organs, while in others they are only developed in a very slight degree, and are utterly useless for purposes of flight. In some species we meet with a rather curious phenomenon, the vast majority of specimens being apterous, while an example occasionally appears in which the wings are fully developed. The Heteroptera are sub-divided into two great groups, known respectively as Gymnocerata and Cryptocerata. The former of these titles signifies, apparent-horned,' and refers to the antennæ, which, in the insects belonging to this group, are long, and are easily seen. This is not the case, however, with the members of the second group, in which the antennæ are very small, and are not visible except upon close examination. The title of Cryptocerata, or 'hiddenhorned,' which has been applied to them, is, therefore, very appropriate. In Mr. Westwood's arrangement these two groups are termed Aurocorisa and Hydrocorisa. The former of these two titles signifies 'air-bugs,' all the insects of the group being dwellers either upon the earth or the surface of the water, beneath the surface of which, however, they are not in the habit of living. But the Hydrocorisa, or water-bugs,' are all inhabitants of the water itself, passing the greater portion of their existence beneath the surface, and only rising occasionally in order to obtain a supply of air. VOL II. A very conspicuous member of the former group is the insect scientifically known as Tropicoris rufipes, but which possesses no popular title. In common with many of its congeners, however, it is often termed a Bishop's Mitre,' in consequence of the peculiar form of the body. This insect is very common towards the end of summer, and may often be seen resting on palings, etc., or on the herbage by the roadside; the brilliant red spot at the apex of the scutellum rendering it a very striking object. The general colour is brown, prettily mottled with black, while the beak, the antennæ, and the legs are of a bright red. In common with many members of the group the Tropicoris possesses a powerful and singularly unpleasant smell, which, if the insect be handled, will cling to the fingers for a considerable time, in spite of repeated lavations. This disagreeable odour is also transmitted to the substances over which the insect walks, fruit of various kinds being often tainted to such a degree as to be rendered perfectly uneatable. It is, however, under the control of the insect, which can exude or retain it at will. It is due to a fluid which passes from two small pores in the hinder tarsi, so that if the insect be carefully seized by the sides of the body, in such a manner that the feet cannot come into contact with the skin, it can be handled with perfect impunity. The odour still clings to the insect for many months after death, and often renders the drawer in which the specimens are contained most terribly offensive to the olfactory organs. The common bed bug (Acanthia lectularia) is also a member of this group. This is one of the apterous species of Heteroptera, the wings being only represented by two very small projections in the place of those organs. This only too familiar insect is not an indigenous inhabitant of England, but is supposed to have been introduced into this country in the course of the last two or three hundred years; from whence, however, we cannot ascertain with any degree of certainty. Once imported, it spread with marvellous rapidity, rivalling the cockroach itself in the speedy manner in which it made its way even to the most remote parts of the country. When once it has taken up its quarters in a room, the bed bug is a most difficult creature to disestablish, its small size and flat body enabling it to creep into the smallest crevices. Within these chinks are deposited the eggs, some fifty or sixty in number, which are always covered with a kind of varnish which hardens upon exposure to the atmosphere, and so fixes them securely to the substance upon which they are laid. The most successful method of destroying these disagreeable insects appears to consist in burning large quantities of sulphur in the room in which they have taken up their residence, having previously stopped up every aperture through which the fatal vapour can possibly escape. After a few weeks the process must be repeated, in order to destroy those specimens which have emerged from the egg subsequently to the former campaign. Passing over a large number of insects, which are of little interest except to those making a special study of the order, we come to the curious group which pass their existence upon the surface of the water,__over which they can glide with considerable speed. These T are known in science as Hydrometrida, or 'water-measurers,' and are so called because they seem to measure the surface of the water with their wonderfully long and slender limbs. Popularly they are known as Watergnats, bearing, as they do, some little resemblance to a gnat from which the wings have been removed. They are to be seen in great numbers in almost every pond, passing along over the surface of the water with astonishing speed. The fore-limbs do not appear to be employed for purposes of locomotion, but are stretched out in front of the body for the purpose of seizing prey. The hinder legs seem to act chiefly in directing the course, while upon the middle pair falls the task of propulsion. In many specimens of water-gnats the wings are not developed, but remain in a rudimentary condition throughout the insect's existence. In others, how Water-gnat (Gerris lacustris). ever, they attain their full dimensions, and are quite capable of bearing their owner through the air. Upon alighting after an aerial excursion, the long hind limbs are employed in tucking the wings beneath the elytra. Included in the Gymnocerata, although not in Mr. Westwood's group of the Aurocorisa, are two very curious and interesting insects, each of which will be described in turn. The first of these is the extraordinary creature known as Ranatra linearis, which would by very few people be recognised as an insect at all. In general appearance it is not unlike a gigantic water-gnat, from which insect, however, it differs in the two long bristle-like appendages springing from the end of the body. Its total length, measured from the extremity of the fore-legs, when fully stretched out, to the end of the bristle-like appendages at the tail, is rather more than three and a half inches, while the extreme width of the body is nowhere greater than oneseventh of an inch. The dull brown colour, slender body, and long limbs render the insect very far from conspicuous amongst the weeds of its native pond, and, until it moves, the creature can hardly be distinguished from the stems of the plants amongst which it is resting. The ranatra, unlike the water-gnats, spends the greater part of its existence beneath the surface of the water, progressing by means of the two hinder pairs of legs. The fore-limbs seem to be used for the purpose of seizing prey alone, and are formed more like jaws than legs; so much so, indeed, that they would certainly be mistaken for those organs by any but an experienced observer. The eggs of the ranatra are deposited in a very singular manner, which has been described by a correspondent of 'Science Gossip,' for November, 1879. He says: On July 7, I was much surprised to find the leaf of frog-bit exhibiting a most unusual appearance; the best verbal description that I can give of this appearance is, that the floating leaf appeared on the top to possess the antennæ of some moth, to which underneath was attached a small substance, something in shape like a canary seed, but more rounded at the extremities, especially at the end from which these antennæ or appanages spring. The leaf had evidently been pierced, and the app anages thrust through, which, opening into a V-like shape, kept the underneath substance from falling. 'I was much puzzled by these appearances, and being quite ignorant of what they were, called in one or two friends to see them, in the hope of acquiring information; but being unable to get any I then more anxiously watched, and almost came to the conclusion that they were the germs of some botanical production. 'The leaf of the frog-bit decaying they gradually sank, the same V-like appanage which had kept them in their position now keeping them from falling too fast or from sinking in the soft mud at the bottom of the aquarium; here they remained in a perpendicular position, and were watched from time to time. On August 4th I was delighted to find four young ranatra swimming freely about. They were about half an inch in length, and in form so like their parents that it was impossible to be deceived. 'The appearance of these young ranatra led to the discovery that the objects on the leaf of the frog-bit which had so puzzled me were the ova of this insect, for I found them all on the bottom of the aquarium quite empty, with an opening in the end between the antennæ or appanages. 'I cannot help thinking what an interesting sight it must have been to have watched the insect depositing the ova, how the leaf must have been pierced, the ova extended, the antennæ-if they may be so calledbeing thrust through the perforated opening, on which they must immediately have sprung into a wedge-like shape-opening wide at the top-to keep the ova in position.' The ranatra is not a very common insect, but may be found in ponds and ditches in many parts of the country. Belonging to the same family as the ranatra is a very different-looking insect, namely, the common Water-scorpion (Nepa cinerea). A very good idea of Water-scorpion (Nepa cinerea). the general appearance of this insect may be obtained by a reference to the accompanying illustration, in which the flat, leaf-like body, the jaw-like fore-legs, and the appendages at the end of the body are very well depicted. The fore-limbs closely resemble those of the ranatra, and are used for a like purpose, namely, that of securing prey. Were it not for the powerful likeness which it bears to the dead leaves and other débris found at the bottom of every pond the water-scorpion would find great difficulty in obtaining food, for its motions are far more sluggish than those of the water-insects, etc., upon which it preys. But, aided by its resemblance to surrounding objects, the insect waits patiently until some luckless victim comes within reach, when it is at once seized by the outspread fore-legs, conveyed to the mouth, and its juices strained by means of the sharp proboscis. The filaments at the end of the tail serve to convey air to the spiracles, which are placed at the end of the body, when the insect is beneath the water, the extremities of those appendages just appearing above the surface while their owner is altogether submerged. Those of the ranatra answer the same purpose. The eggs of the water-scorpion are of a very singular form, being furnished with seven horn-like projections, arranged in a circle, by means of which they are fastened to the leaves of various water-plants, just as is the case with those of the preceding insect. Although the water-scorpion almost invariably seeks its prey beneath the water, I know of one case, which came under my personal observation, in which there was an exception to this rule. While standing, one warm summer's day, upon the banks of a small pond, which had been partly dried by the heat of the weather, I noticed a fly struggling in the mud which surrounded the edge of the water, and apparently in the grasp of some invisible adversary. Upon investigating the matter, I found that a waterscorpion had buried itself in the mud, with the jaws just projecting above the surface, and had seized the fly as it passed along unconscious of the presence of its enemy. The whole proceeding, in fact, bore a considerable resemblance to the mode of capture of prey followed by the ant-lion. Although a very dull and sombre-looking insect when creeping slowly amongst the debris of the pond, the water-scorpion is really quite a handsome creature when the wings are spread in flight. The basal portion of the lower pair, as well as the greater part of the upper surface of the abdomen, are then seen to be of a brilliant red colour, which really renders the insect a striking object. The water-scorpion is a very plentiful insect, and may be taken in numbers from any weedy pond. Now we come to the second of the two great groups of Heteroptera, namely, the Cryptocerata, or those in which the antennæ are concealed from view. The most interesting of these, perhaps, is the common Water-boatman (Notonecta glauca), which we will accordingly take as a type of the group. In the accompanying woodcut the position generally assumed by the boatman when swimming, or resting upon the surface of the water is very well repre Water-boatman (Notonecta glauca). sented. In this curiously reversed position the insect passes the greater part of its existence in the water, and may be seen in numbers in almost any pond, resting motionless upon the surface of the water, unless disturbed by the shadow of a passer-by. Sometimes, however, on a fine and sunny morning, the boatman will turn over, and assume a rather remarkable attitude, resting upon the surface of the water with the elytra opened and the wings partially protruding. The name of 'boatman' is wonderfully appropriate, the insect, in its reversed position, bearing a most striking resemblance to a boat with two long oars projecting from it. And the long hind limbs really take the place and fulfil the functions of oars, being fringed with long hairs, just as is the case with those of the Dyticus and other aquatic beetles, in order that they may offer a greater resistance to the water. The term 'Notonecta' is also appropriate, that word signifying a 'back-swimmer,' and referring to the attitude assumed by the insect when in the water. The feathering' principle, if we may so call it, of the swimming legs, is also quite as strongly marked as in the water-beetles, the limb mechanically turning sideways for the reverse stroke, and so presenting the edge only to the water, through which it cleaves without difficulty. The respiratory system, too, is of much the same order, the space between the wings and the abdomen forming a kind of reservoir for the reception of air. Thus provided, the insect can spend a considerable time beneath the water without requiring to seek the surface in order to procure a fresh supply. The wings of the notonecta are large and powerful, and are well adapted to bear their owner through the air. The insect is able to take to flight from the surface of the water, which it does as follows: First, diving to some little distance, it reverses its position so as to bring its head upwards; then, swimming rapidly towards the surface, it gives a smart stroke with the hinder legs, and so projects itself a few inches into the air. The wings are then immediately spread, and the insect flies off before it has time to fall back into the water. (Some years ago, I had a number of waterboatmen in an aquarium. Seeing, to my great surprise, that they took to wing from the surface of the water, I leaned over the aquarium and looked into it. Presently, one of the insects dived, as has just been mentioned, sprang into the air, struck me on the nose, and fell back into the water. I wonder which was the more surprised, the insect or myself.-J. G. WOOD.) The water-boatman is a very predacious creature, and seems to possess a particular fondness for the watergnats, which it captures without difficulty as they are resting upon the surface of the water. In a very few moments the body is drained of its juices, and the boatman casts it aside and looks out for another victim. The proboscis of the water-boatman is very sharp and strong, and is capable of inflicting a rather painful wound upon the fingers if the insect be not properly held. The saliva appears to possess a decidedly poisonous quality, as the wounded finger will swell and ache for hours in a manner which could scarcely be caused by the puncture alone. Both the larva and pupa of the water-boatman bear a very strong resemblance to the perfect insect, from which, however, they can easily be distinguished by the absence of wings. In the former stage of development these organs are altogether wanting, while in the pupa they are quite rudimentary in size. Closely allied to the water-boatman are a number of insects included under the generic title of Corixa, many of which are exceedingly plentiful in every pond. In habits and general appearance these little creatures closely resemble the preceding insect, from which they may be distinguished by several points of structure, such as the form of the body, which is flat instead of convex, etc. (To be continued.) |