- Cærostris Mitralis
- Cærostris Mitralis, in profile
- Dancing Mania
- Demodex folliculorum
- Dermanyssus gallinæ, female
- Dermatophilus penetrans
The chigoes, or true chiggers, are the most completely parasitic of any of the fleas. Of the dozen or more known species, one commonly attacks man. This is Dermatophilus penetrans, more commonly known as Sarcopsylla penetrans or Pulex penetrans. This species occurs in Mexico, the West Indies, Central and South America. The males and the immature females of Dermatophilus penetrans closely resemble those of other fleas. They are very active little brown insects about 1-1.2 mm. in size, which live in the dust of native huts and stables, and in dry, sandy soil. In such places they often occur in enormous numbers and become a veritable plague. - Diagram of a longitudinal section of a mosquito
It is well known that mosquitoes, when they bite, inject into the wound a minute quantity of poison. The effect of this varies according to the species of mosquito and also depends very much on the susceptibility of the individual. Soon after the bite a sensation of itching is noticed and often a wheal, or eminence, is produced on the skin, which may increase to a considerable swelling. The scratching which is induced may cause a secondary infection and thus lead to serious results. Some people seem to acquire an immunity against the poison. The purpose of this irritating fluid may be, as Reaumur suggested, to prevent the coagulation of the blood and thus not only to cause it to flow freely when the insect bites but to prevent its rapid coagulation in the stomach. Obviously, it is not developed as a protective fluid, and its presence subjects the group to the additional handicap of the vengeance of man. As to the origin of the poison, there has been little question, until recent years, that it was a secretion from the salivary glands. Macloskie (1888) showed that each gland is subdivided into three lobes, the middle of which differs from the others in having evenly granulated contents and staining more deeply than the others. - Dipylidium caninum. Rostrum evaginated and invaginated
- Dipylidium caninum. The double pored tapeworm of the dog
- Dog flea
- Dome-like House of Cicada
Longitudinal Section Showing Pupa in Two Positions. In localities where the soil is low and swampy, a remarkable chamber is built up by the larva, where the pupa may be found awaiting the time of its change to the winged state. These chambers were first noticed by S. S. Rathvon, at Lancaster, Pa., and are from four to six inches above the ground, and have a diameter of one inch and a quarter. When ready to emerge the insect backs down to an opening which is left in the side of the structure on a level with the surface of the ground, issues forth and undergoes its transformation in the usual manner. This peculiar habit of nest-building, which is so unlike what is customary with the Cicadidæ, or with Hemiptera in general, points to a high degree of intelligence among these insects, showing a remarkable ability to adapt themselves to environing circumstances. - Dorcus punctulatus
Dorcus punctulatus - Drassidæ
A large family of spiders, varying greatly in shape, color, and habits. Most of them are dull colored, and live under stones, or in silk tubes on plants, and make no webs for catching insects. Their eyes are small, and arranged in two rows on the front of the head. Their feet have two claws and a bunch of flat hairs. The spinnerets are usually long enough to extend a little behind the abdomen. The figure is a Drassus, and the eyes as seen from in front. - Dryocora howittii
Dryocora howittii - Dryocora howittii - Larva
Dryocora howittii - Larva - Dysderidæ
Dysdera Interrita A small family of spiders with only six eyes. They have also four breathing-holes in the front of the abdomen; but one pair leads to branched tubes instead of sacs. They are usually found under stones, with their legs drawn up close to their bodies, but can move very quickly when so inclined. Very few species are known, and none are common, in North America. At bottom of figure are the eyes as seen from in front. - Echidnophaga gallinacea
- Egg-capsule of P. orientalis
A external view B opened C end view. The eggs of the Cockroach are laid sixteen together in a large horny capsule. This capsule is oval, with roundish ends, and has a longitudinal serrated ridge, which is uppermost while in position within the body of the female. The capsule is formed by the secretion of a “colleterial” gland, poured out upon the inner surface of a chamber (vulva) into which the oviducts lead. The secretion is at first fluid and white, but hardens and turns brown on exposure to the air. In this way a sort of mould of the vulva is formed, which is hollow, and opens forwards towards the outlet of the common oviduct. Eggs are now passed one by one into the capsule; and as it becomes full, its length is gradually increased by fresh additions, while the first-formed portion begins to protrude from the body of the female. When sixteen eggs have descended, the capsule is closed in front, and after an interval of seven or eight days, is dropped in a warm and sheltered crevice. In Periplaneta orientalis it measures about ·45 in. by ·25 in. - Eggs of Anopheles
- Epithelium underlying poison hairs of the larva of the browntail moth
- Epithelium underlying poison hairs of the larva of the browntail moth (larger scale)
- Evania appendigaster
- Every good mother should be the honored queen of a happy family
The group of bees represents the attitude in which the bees surround their Queen or Mother as she rests upon the comb. - Field Scorpion
Field Scorpion ( Buthus occitanus ): - a) top viw.-b) ventral side of the abdomen prior to: the 1st section - Fight between an Ordinary Roller Spider and a Scorpion
The Roller Spider hides during the day in crevices of the loamy soil, in reed beds or under stones; at night she goes out for robbery and catches Insects. Tests on large specimens have shown that she also attacks large animals. A 52 mm Roller Spider. body length grabbed a 105 mm. long Scorpion at the root of the tail, bit it off and then devoured the whole animal. However, this victory was only due to chance, as it turned out, when a second Scorpio was brought to her and she attacked them from the front; this animal held its enemy with the claws and wounded it with the poison spine, to which it succumbed after a few convulsions. {trasnslated by Google] - Filaria in the muscles and labium of Culex
When the blood of an infested individual is sucked up and reaches the stomach of such a mosquito, the larvæ, by very active movements, escape from their sheaths and within a very few hours actively migrate to the body cavity of their new host and settle down primarily in the thoracic muscles. There in the course of sixteen to twenty days they undergo a metamorphosis of which the more conspicuous features are the formation of a mouth, an alimentary canal and a trilobed tail. At the same time there is an enormous increase in size, the larvæ which measured .3 mm. in the blood becoming 1.5 mm. in length. This developmental period may be somewhat shortened in some cases and on the other hand may be considerably extended. The controlling factor seems to be the one of temperature. The transformed larvæ then reenter the body cavity and finally the majority of them reach the interior of the labium. A few enter the legs and antennæ, and the abdomen, but these are wanderers which, it is possible, may likewise ultimately reach the labium, where they await the opportunity to enter their human host. - Flea
The strength and beauty of this small creature, had it no other relation at all to man, would deserve a description. For its strength, the Microscope is able to make no greater discoveries of it then the naked eye, but onely the curious contrivance of its leggs and joints, for the exerting that strength, is very plainly manifested, such as no other creature, I have yet observ'd, has any thing like it; for the joints of it are so adapted, that he can, as 'twere, fold them short one within another, and suddenly stretch, or spring them out to their whole length, that is, of the fore-leggs, the part A, of the Scheme, lies within B, and B within C, parallel to, or side by side each other; but the parts of the two next, lie quite contrary, that is, D without E, and E without F, but parallel also; but the parts of the hinder leggs, G, H and I, bend one within another, like the parts of a double jointed Ruler, or like the foot, legg and thigh of a man; these six leggs he clitches up altogether, and when he leaps, springs them all out, and thereby exerts his whole strength at once. - Flea
- Flowers
- Foot of Attus Mystaceus
In many spiders a brush of hairs takes the place of the middle claw, as in the jumping spiders. Spiders with these brushes on their feet can walk up a steep surface, or under a horizontal one, better than those who have three claws. - Foot of Epeira Vulgaris
The legs are used chiefly for running, jumping, and climbing; but the front pair serve often as feelers, being held up before the body while the spider walks steadily enough on the other six. One or both of the hinder legs are used to guide the thread in spinning; the spider at the same time walking or climbing about with the other six or seven. The legs are seven-jointed; and on the terminal joint are three claws ( A, B, C) and various hair and spines. - Freshly hatched larva of Julus multistriatus
Freshly hatched larva of Julus multistriatus? 3 mm. long: a, 5 pairs of rudimentary legs, one pair to a segment. - Garden spider
Garden spider ( Epeira diadema ): - 1) Female. 2) Male. 3) Spider pipe. 4) Spinnerets with the vent opening (top) and the “strainer” (bottom). 5) Jaw blades and eyes. 6) Left jaw blade, the ground member of which is cut longitudinally to show the venom gland as a whole. 7) Top of the foot lid. 3–7 strongly enlarged. - Gecko, chasing cockroaches
- Harlequin Spider
Harlequin Spider ( Salticus scenicus ): a) Female, b) Male, both enlarged. c) Female, full size, d) Front part of the head bust, seen from behind to show eye placement (enlarged). - Harvest mites. (Larvæ of Trombidium)
- Head and pronotum of (a) dog flea; (b) of cat flea; (c) of hen flea (d) Nycteridiphilus (Ischnopsyllus) hexactenus
- Head of a spider showing poison gland (c) and its relation to the chelicera (a)
- House spider
House spider ( Tegenaria domestica ): - a) Male (below, on an enlarged scale, eyes seen from the front). b) Female - House-builder Moth
Young in House, Winged Male, Young Suspended and Bag-like Female in Longitudinally-Split Cocoon. During the winter the curious weather-beaten bags of these worms may be observed hanging from the tree-branches, apparently without a trace of the odd-looking creatures that hung them there the autumn before. If a number of these bags are gathered and cut open at this time, many of them will be discovered to be empty, but the greater portion will be found partly full of yellow eggs. Those which do not contain eggs are male bags, and the empty chrysalis of the male will be found protruding from the lower extremity. Upon close examination these eggs will be observed to be obovate in form, soft and opaque, about one-twentieth of an inch in length, and surrounded by more or less fawn-colored silky down. If left to themselves, they hatch sometime in May, or early in June. - Insect frame
- Insect Frame 2
- Insect Frame 3
- Insect Frame 4
- Ixodes ricinus; male, ventral aspect
- Larva of a flesh fly (Sarcophaga) - Caudal aspect - Anterior stigmata. Pharyngeal skeleton
Sarcophagidæ—The larvæ of flies of this family usually feed upon meats, but have been found in cheese, oleomargerine, pickled herring, dead and living insects, cow dung and human feces. Certain species are parasitic in insects. Higgins (1890) reported an instance of "hundreds" of larvæ of Sarcophaga being vomited by a child eighteen months of age. There was no doubt as to their origin for they were voided while the physician was in the room. There are many other reports of their occurrence in the alimentary canal. We have recorded elsewhere (Riley, 1906) a case in which some ten or twelve larvæ of Sarcophaga were found feeding on the diseased tissues of a malignant tumor. The tumor, a melanotic sarcoma, was about the size of a small walnut, and located in the small of the back of an elderly lady. - Larva of Anopheles
- Larva of Auchmeromyia luteola
The whitish larvæ on hatching are slightly flattened ventrally, and each segment bears posteriorly three foot-pads transversely arranged. At night the larvæ find their way into the low beds or couches of the natives and suck their blood. - Larva of Fannia scalaris
- Larva of Forficula
Larva of Forficula - Larva of Pulex irritans
- Larva of Simulium
- Larva of Xenopsylla cheopis
- Leaf-Cutter Bee at Work
Two Tunnels Being Filled With Leaf-Cells. You should see the little creature in her never-tiring work of preparing material for her nest. In and out among the roses she goes, examining each leaf with the most critical care, and only desisting from her labor when a suitable one has been chosen. She scans it over and over, and at last from a position on its upper or nether surface proceeds to cut a piece just fitted for her work, which, heavy as it seems, is seized between the legs and jaws and carried on swiftly-agitated wings to her burrow. Ten pieces or more, each differing in shape, are cut and borne away, which the ingenious insect tailor twists and folds, the one within the other, until is formed a funnel-like cone, whose end is narrower than its mouth. So perfectly joined are the parts, that even when dry they have been found to retain their form and integrity. A cake of honey and pollen, for the use of some yet unborn Leaf-cutter, is deposited within, and on this, in due time, is laid a single small egg. Nought now remains but to wall up the cell. A circle of leaf, of the size of the opening, is cut, and this is closely adjusted within the wall of rolled-up leaves. Sometimes as many as four pieces are thus utilized. A second cell, similarly built, is fitted to the first, and this is succeeded by eight or ten others. When all is completed, the eggs being laid and the cells all victualled, the hole of the shaft is closed with the earth that was thrown out, and so carefully, too, that not a trace of her doings remains to tell us the story. - Left hand stigmata of the larvæ of muscoidea
- Left spiracle of nymph of Argas persicus
- Lepismas at Work
Living in chinks and crannies of ranges in our homes, and occasionally in bookcases and closets where glutinous and sugary matters abound, but which has probably not been met with elsewhere, is a strange but beautiful little creature which, as far as can be determined, goes through the brief round of its existence without a name to distinguish it from its fellows. Few entomologists have given any special attention to its family relationships. The possession of certain bristle-like appendages which terminate the abdomen, and which are no doubt comparable with the abdominal legs of the Myriopods, or Thousand Legs, classes it with the Bristle-tails, or Lepismas. In general form, a likeness to the larva of Perla, a net-veined neuropterous insect, is manifest, or to the narrow-bodied species of Blattariæ, or Cockroaches, when divested of wings. - Life cycle of the malarial parasite
- Linguatula. (a) larva; (enlarged). (b) adult; (natural size)
- Locust
There has already been talk of the plague of the intestinal worms and their expulsion by Kusso; the higher standing insects occur in the highlands in large quantities only in the warmer season, but are driven back into the lower lying areas by the cold rains. The locusts , Amharic Anbasa, often cause great damage, as in the other Nile countries.