Sir A. E. Shipley

“ Insects are not only highly intelligent animals, but are by far the most numerous and dominant class of the Animal Kingdom; [Pg 3] and they have probably come to conclusions about themselves and the sea, comparable to those expressed by Dr. Johnson about man and the ocean: ‘To all the inland inhabitants of every region the sea is only known as an immense diffusion of waters, over which men pass from one country to another, and in which life is frequently lost.’
But one insect at least causes more trouble to sailors than to soldiers—and that is the cockroach. ”

“ The male nourishes itself on plant-juices, saps, and so on—especially they like sugary secretions—and in the absence of blood the female is reduced to a similar diet. Hence Stegomyia is comparatively common in dwellings where sweetstuffs are—bakeries, sugar-refineries, and so on. These mosquitos are, like the cockroach, the fly, and the bed-bug, inhabitants of human dwellings. They are indeed domesticated, and are always to be found in the neighbourhood of human houses or buildings or ships, and are very rarely indeed found far away from the sphere of man’s activities. ”

“ That the male should be endowed with superior acuteness of the sense of hearing appears from the fact that he must seek the female for sexual union either in the dim twilight or in the dark night, when nothing save her sharp humming noise can serve him as a guide. ”

“ In ‘The Minor Horrors of War,’ we rather neglected the Navy—the senior Service, and till now the more dominant of our two magnificent forces—partly because it is less interfered with by insect pests than is the sister Service, though the common pests of our poor humanity—the flea, the louse, the bug—are, like the poor, ‘always with us.’ Like aeroplanes, insects have captured the air; like motors, they have made a respectable show on land ”

“ It is not perhaps solely the influence of light; it may be the influence of colour; for light is very rarely entirely colourless. In the many experiments carried on in Cambridge on the natural history of the mosquito, A. maculipennis, not the least interesting were those directed to ascertaining the insect’s preference for colour. It had been noticed by many observers that they frequented dark-coloured areas rather than light: for instance, note how few mosquitos there are on the white collar of the gentleman in the Frontispiece compared with the number on his dark head and coat. ”

“ Like the bed-bug, the cockroach came into England at the end of the sixteenth century, and, like the bed-bug, it came from the East. It seems to have been first introduced into England and Holland in the spacious times of Henry VIII by the cross-sea traffic, and from about the end of the sixteenth century the cockroach began gradually to spread throughout the Western world. Like the rat, the bed-bug, and the domestic fly, it has become thoroughly acclimatised to human habitations, and is indeed an associate of man. It is very rarely found living apart from some form or other of human activity. ”

“ I have no doubt my publisher is right, because if publishers were not invariably right, and authors invariably wrong, how can one explain the fact that publishers are proverbially prosperous and prominent people, whereas authors are notoriously penniless and obscure? ”

“ It seems odd that an insect pest, which so seriously affects our supply of leather, of meat, and of milk, should have been studied for over a century and yet conceal its chief secret from man. But the problem is much more difficult than the layman thinks. ”

“ In the young larva of Anopheles the head is broader and deeper than the thorax, but in the older larvae the segments that succeed the head have at least twice its diameter. It is a characteristic of true flies, or Diptera, that the thorax should not exhibit that separation into three divisions which is so usual in the less specialised insects—such as the cockroach and this is peculiarly true of the larva of the mosquito—at any rate, so far as its external structure goes. The abdomen of the larva consists of nine free segments ”

“ The hairs are capable of movement, and as a rule are kept closed on the shaft of the antenna whilst not in use; when evening comes on they are spread out. There seems little doubt that these organs are auditory and help the male in searching for the female.
The beautiful transparent wings of the mosquito are beset with minute spikes, which serve to break up the light and to give rise to the many-coloured iridescence of the creature’s wings. The posterior border of the wing bears rows of beautifully graded scales. These add much to the symmetry and beauty of the whole structure. ”

“ From what has been said it is obvious that rats cause enormous damage to humanity, which is counterbalanced by the almost infinitesimal good they do as scavengers. I do not propose to consider in detail the harm they do as disease-carriers, but one cannot forget that the rat is the primary host of Trichinella spiralis, which, when conveyed from the rat to the pig, and—by eating uncooked or imperfectly cooked pork—from the pig to man, causes severe and very fatal epidemics, and enforces the expenditure of large annual sums on meat inspection. ”

“ The young imago is pale in colour, the thorax being brown and the abdomen transparent, with a greenish tinge. At first the abdomen is much longer than it is later, for, almost immediately after the mosquito’s exit from the pupa-case its abdomen begins to contract, and from its hinder end four or five drops of a glistening, greenish-white fluid are exuded.
The newly born imagines generally take to flight between five and ten minutes after they have emerged, and they at once begin to darken in colour, and in two hours assume the normal dusky colour of the adult. ”

“ The genus Stomoxys is generally called in Great Britain the ‘stable-fly,’ but there are other ‘stable-flies.’ One of the commonest species of the genus is S. calcitrans, a two-winged muscid fly, not at all unlike the common domestic fly, Musca domestica; but there are one or two points which readily distinguish [Pg 126] it from the commoner insect. To begin with: it has a hard, firm, chitinous, piercing proboscis, which when at rest stretches forward in front of the head, and when in action is pressed down at right angles to the longitudinal axis of the body ”

“ Many other blood-sucking insects, whose puncture must involve some pain, are tolerated by cattle with a flick of the tail, or are frightened off by a gesture of the head; but the presence of the warble-fly induces a mysterious fear which rapidly spreads through a herd, and results in a general stampede—often referred to by cattle-breeders as the ‘gad.’ This terror communicates itself even to the [Pg 41] ‘stalled ox,’ and cattle confined within cowsheds show symptoms of extraordinary unrest when the fly is abroad amongst their kin in the pastures. ”

“ No one ever slept in the tent, and I never found Anopheles bite in the day-time.
The best way of ‘downing’ mosquitos is to prevent the imago hatching, and this, as has been indicated, can be done by killing the larvae and the pupae, which is effected by brushing oil on the water in which they live. The petrol or crude mineral oil should be renewed from time to time as it evaporates. When once the mosquitos are hatched, every effort should be made to keep them outside dwelling-houses by means of wire screens, but if that be impracticable mosquito-nets should be used at nights. ”

“ Their fondness for bulbs is a great nuisance to the Dutch tulip-merchants. As many as 300 have been trapped in a fortnight in a single crocus-bed. They are also a nuisance to bee-keepers, inasmuch as they enter the hive and eat the honeycomb, especially during the winter. Whilst feeding in the hedgerows, or undergrowth, they frequently establish themselves in birds’ nests, and occasionally such nests become their permanent home. ”

“ The hind legs not infrequently serve as a test for food. When feeding upon sweetened milk or fruit, the moment the hind leg touches the fluid or juice the insect will wheel round and at once begin to feed.
Anopheles maculipennis is very widely distributed, and it has been recorded from most parts of North America and Europe, and from many parts of Asia. Probably the species is much more widely distributed than we have any record, but individuals do not wander very far, of their own accord, from the breeding-places, though they may be dispersed by the wind. ”

“ The adult fly feeds upon any decaying matter; but whenever it can, it sucks the blood of vertebrates, and at times is a real nuisance to animals as well as human beings. So voracious are they that should a well-fed one be injured, the others immediately attack it and suck up every drop of blood which it had secured for its own food.
It has often been disputed whether a meal of blood is essential to the female mosquito before oviposition, but it seems perfectly clear that the female Stomoxys can produce fertilised eggs without having had a meal of blood.
[Pg 129] ”

“ During the pupa stage Anopheles, like the pupa of other insects, takes no food.
The pupa is something like a tadpole, with its tail bent under its body and flapping up and down, instead of from side to side. The whole pupa is enclosed in a thin semitransparent membrane, through which the organs of the adult can readily be seen. As it grows older its colour darkens. Until about the time when it will give rise to the fly, the pupa floats quietly at the surface, breathing through its respiratory trumpets. ”

“ Grassi says he never found the male of A. maculipennis in the winter, only fertilised females. But as the warm weather sets in the female generally becomes active and bites, and the native American Indians consider these elderly and famished females give more annoyance than at any other stage in the life-cycle of either sex. In the warmer climate of Southern Italy they not infrequently hibernate in grottos and caves. At times they occur in such numbers that they can be swept up. After depositing their eggs the hibernating females probably die. ”

“ There has always been some divergence of opinion as to how the buzzing sound to which the male so readily reacts is produced. Howard once thought that it was due to vibrations of certain chitinous processes in the large tracheae. Our experiments showed, however, that when the wing was cut off closer and closer to its origin the sound decreased in volume, but the note progressively rose. Unlike human beings, the male at all times emits a higher pitched note than the female, and in both sexes the note rises after feeding. ”

“ Both Anopheles and Culex—at any rate, in captivity—lay their eggs early in the morning. Apparently the nature of the food has some effect upon their fertility, certain observers stating that when male and female are fed on vegetable food alone there is no fertilisation and no oviposition. A diet of blood evidently assists the female to lay her eggs, and perhaps to get them fertilised. One of our female Anopheles laid a batch of 146 eggs, and subsequently laid six more. But, as a rule, a fertilised female does not lay a second batch unless she receives a second meal of blood. ”

“ Each egg is fertilised by a spermatozoon which has been deposited by the male in the spermatheca of the female. The eggs are placed in a double row, eight in each row, facing each other, and, as they gradually develop, it becomes apparent that the ventral face of one row faces the ventral face of the other row—just as the little choir-boys on the Gospel side of a chancel face the little choir-boys on the Epistle side, but much nearer together—and that their heads are all directed towards the corrugated ridge. ”

“ Another member of the Muridae, the field-mouse (Apodemus sylvaticus) , is almost as great a nuisance in the trenches as the rat. The field-mouse is very like the house-mouse, with some of its features seen under a lens. The hind feet and ears and eyes are larger than are those of the house-mouse. Perhaps its much longer hind legs help most easily to differentiate the two species. ”

“ In England they can undoubtedly feed twenty-four hours after leaving the pupa-case. When feeding, both the sensory antennae and the tactile maxillary palps are thrust forward at right angles to the proboscis. They thus test the place where the two-lobed extremity of the labium will guide the battery of stylets into the substance they are feeding on. The female is much more voracious than the male, which, as we have mentioned above, cannot pierce the human integument, and has to be content with a vegetarian diet. ”

“ It is the hinder wings which really do the active flying. After a flight, the hinder wings are shut up something in the manner of a fan.
The flattened coxae, or thighs, of the leg are adapted for shovelling débris back from beneath the body when the insect is enlarging its habitation. When the cockroach gets into a dusty ‘milieu’ the dust is immediately removed; the hairs on the legs act as clothes-brushes and brush every part of the body, whilst the antennae, which attract any dust in the neighbourhood, are repeatedly drawn through the closed mandibles and so cleaned. ”

“ How exactly these nematode larvae leave the labium of the mosquito, and enter the body of the man and the dog, has not definitely, I believe, been cleared up; but that they do enter the human and the canine skin seems certain.
We have mentioned that the labrum is a grooved tube with its edges practically in proximity, and it is up this tube that the blood of the bitten is sucked by the well-known suctorial pharynx which occupies so large a part of the interior of the head of a mosquito. Much the most dangerous weapon of the whole armoury, however, is the hypopharynx. ”

“ In fact, the methods that have been advocated for the common house-fly are applicable to Stomoxys. If stable manure were carefully removed, from May to October, at least every seven days, the number of flies would be materially reduced. Where this is impracticable, manure-heaps should be covered with some insecticide, so as to destroy the eggs and larvae. Experiments are still being made with the view of finding a substance capable of killing the eggs, larvae, and pupae, which will be at once cheap and unharmful to the fertilising value of the manure. ”