- Sarcoptes scabiei, male
- 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. - Section through a venom gland of Latrodectus 13-guttatus showing the peritoneal, muscular and epithelial layers
- Dog flea
- Left hand stigmata of the larvæ of muscoidea
- Dipylidium caninum. Rostrum evaginated and invaginated
- 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. - Calliphora erythrocephala
- The Caterpillar of the Small Elephant Hawk-moth (Chærocampa porcellus)
- The yellow fever mosquito (Aëdes calopus)
- 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. - The Locust
Sometimes millions of locusts come upon the wind, and devour every green thing, so that nothing is left for man or beast. - Epithelium underlying poison hairs of the larva of the browntail moth
- Cross section of the larva of the browntail moth showing the tubercles bearing the poison hairs
- The Caterpillar of the Marbled White Butterfly (Arge galathea)
- Poison apparatus of a honey bee
- Long-armed Tarantel Scorpion
Long-armed Tarantel Scorpion ( Phrynus lunatus ) - a) Front part of the head bust enlarged to show the arrangement of the eyes. - Mandible of Scolopendra cingulata showing venom gland
- House spider
House spider ( Tegenaria domestica ): - a) Male (below, on an enlarged scale, eyes seen from the front). b) Female - Sauvage's Mason Spider
Sauvage's Mason Spider ( Cteniza fodiens ) in her home (this is greatly shortened and shown cut lengthways) .— a) Placement of eyes (greatly enlarged) .— b) Cover seen from the inside. -C) Eggs. ). - The Caterpillar of the Elephant Hawk-Moth (Chærocampa elpenor). First stage
- Rasahus biguttatus
- Dermanyssus gallinæ, female
- Muscina stabulan
- Salivary glands of Notonecta maculata
- Pediculus showing the blind sac (b) containing the mouth parts (a) beneath the alimentary canal (p)
- Dipylidium caninum. The double pored tapeworm of the dog
- Field Scorpion
Field Scorpion ( Buthus occitanus ): - a) top viw.-b) ventral side of the abdomen prior to: the 1st section - The house or typhoid fly (Musca domestica)
The house-fly breeds by preference in horse manure. Indeed, It has been found that they would develop in almost any fermenting organic substance. Thus, they have been bred from pig, chicken, and cow manure, dirty waste paper, decaying vegetation, decaying meat, slaughter-house refuse, sawdust-sweepings, and many other sources. A fact which makes them especially dangerous as disease-carriers is that they breed readily in human excrement. - Xenopsylla cheopis, male
- Culicoides guttipennis - (a) adult, (×15) (b) head of same (c) larva (d) head (e) pupa
- Ornithodoros moubata
(a) Anterior part of venter (b) second stage nymph (c) capitulum (d) dorsal aspect of female (e) ventral aspect of female (f) ventral aspect of nymph (g) capitulum of nymph Ornithodoros moubata, the carrier of African relapsing fever, or "tick-fever," is widely distributed in tropical Africa, and occurs in great numbers in the huts of natives, in the dust, cracks and crevices of the dirt floors, or the walls. It feeds voraciously on man as well as upon birds and mammals. Like others of the Argasidæ, it resembles the bed-bug in its habit of feeding primarily at night. Dutton and Todd observed that the larval stage is undergone in the egg and that the first free stage is that of the octopod nymph. - Stomoxys calcitrans - adult, larva, puparium and details
Stomoxys calcitrans, the stable-fly—It is a popular belief that house-flies bite more viciously just before a rain. As a matter of fact, the true house-flies never bite, for their mouth-parts are not fitted for piercing. The basis of the misconception is the fact that a true biting fly, Stomoxys calcitrans , closely resembling the house-fly, is frequently found in houses and may be driven in in greater numbers by muggy weather. From its usual habitat this fly is known as the "stable-fly" or, sometimes as the "biting house-fly." - Sarcoptes scabiei. Diagrammatic representation of the course in the skin of man
- Cærostris Mitralis
- Head and pronotum of (a) dog flea; (b) of cat flea; (c) of hen flea (d) Nycteridiphilus (Ischnopsyllus) hexactenus
- Trypanosoma brucei
By trypanosomiasis is meant a condition of animal parasitism, common to man and the lower animals, in which trypanosomes, peculiar flagellate protozoa, infest the blood. Depending upon the species, they may be harmless, producing no appreciable ill-effect, or pathogenic, giving rise to conditions of disease. A number of these are known to be transferred by insects. The trypanosomes are elongated, usually pointed, flagellated protozoa in which the single flagellum, bent under the body, forms the outer limit of a delicate undulating membrane. It arises near one end of the organism from a minute centrosome-like body which is known as the blepheroplast, and at the opposite end extends for a greater or less distance as a free flagellum. Enclosing, or close beside the blepheroplast is the small kinetonucleus. The principal nucleus, round or oval in form, is situated near the center of the body. Asexual reproductions occurs in this stage, by longitudinal fission, the nucleus and the blepheroplast dividing independently of one another. From the blepheroplast of one of the daughter cells a new flagellum is formed. - Cockroach
A female cockroach, Periplaneta, with the dorsal exoskeleton removed, dissected to show the viscera. 1 Head 2 labrum 3 antenna, cut short 4 eye 5 crop 6 nervous system of crop 7 gizzard 8 hepatic caeca 9 mid-gut or mesenteron 10 Malpighian tubules 11 colon 12 rectum 13 salivary glands 14 salivary receptacle 15 brain 16 ventral nerve cord with ganglia 17 ovary 18 spermatheca 19 oviduct 20 genital pouch, in which the egg-cocoon is found 21 colleterial glands 22 anal cercus (From Latter. - Tarantula
Tarantula ( Mygale ). - Piophila casei
- 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. - Cockroach-hunting wasps
Cockroach-hunting wasps. A, Dolichurus stantoni leading a nymph of Blattella lituricollis to her nest, c. X 4. B, Podium haematogastrum attaching her egg to an Epilampra sp. while on the side of a termite mound that contains the wasp's nest, c. X 1.6. C, Epilampra sp. parasitized by P. haematogastrum showing the wasp's egg attached to the right fore coxa, c. X 3.2. - Otiobius (Ornithodoros) megnini, head of nymph
- Spirochæta gallinarum. After Hindle.
Spirochætosis of Fowls—One of the best known of the spirochætes transmitted by arthropods is Spirochæta gallinarum, the cause of a very fatal disease of domestic fowls in widely separated regions of the world. According to Nuttall, it occurs in Southeastern Europe, Asia, Africa, South America and Australia. In 1903, Marchoux and Salimbeni, working in Brazil, made the first detailed study of the disease, and showed that the causative organism is transmitted from fowl to fowl by the tick Argas persicus. They found that the ticks remained infective for at least five months. Specimens which had fed upon diseased birds in Brazil were sent to Nuttall and he promptly confirmed the experiments. - 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. - Larva of Xenopsylla cheopis
- Butterfly
Butterfly - Mouth appendages of cockroach
Mouth appendages of Periplaneta (magnified). A Mandible B First maxilla 1 cardo 2 stipes 3 lacinia 4 galea 5 palp C Right and left second maxillae fused to form the labium 1 submentum 2 mentum 3 ligula, corresponding to the lacinia 4 paraglossa, corresponding to the galea 5 palp (From Latter.) - Beak of hemipteron
Several families of the true bugs include forms which, while normally inoffensive, are capable of inflicting painful wounds on man. In these, as in all of the Hemiptera, the mouth-parts are modified to form an organ for piercing and sucking. The upper lip, or labrum, is much reduced and immovable, the lower lip, or labium, is elongated to form a jointed sheath, within which the lance-like mandibles and maxillæ are enclosed. The mandibles are more or less deeply serrated, depending on the species concerned. - Flowers
- Flea
- A millipede
The Diplopoda, or millipedes, are characterized by the presence of two pairs of legs to a segment. The largest of our local myriapods belong to this group. They live in moist places, feeding primarily on decaying vegetable matter, though a few species occasionally attack growing plants. The millipedes are inoffensive and harmless. Julus terrestris, and related species, when irritated pour out over the entire body a yellowish secretion which escapes from cutaneous glands. It is volatile, with a pungent odor, and Phisalix (1900) has shown that it is an active poison when injected into the blood of experimental animals. This, however, does not entitle them to be considered as poisonous arthropods, in the sense of this chapter, any more than the toad can be considered poisonous to man because it secretes a venom from its cutaneous glands. - Cockroach
Periplaneta orientalis, male. Side view. 1 Antenna 2 head 3 prothorax 4 anterior wing 5 soft skin between terga and sterna 6 sixth abdominal tergum 7 split portion of tenth abdominal tergum 8 cercianales 9 styles 10 coxa of third leg 11 trochanter 12 femur 13 tibia 14 tarsus 15,claws (From Kükenthal.) - Mosquito
Anopheles crucians. Female - Gecko, chasing cockroaches
- Bees on clover
- Larva of Forficula
Larva of Forficula - Aëdes calopus; larva
The yellow fever mosquito breeds in cisterns, water barrels, pitchers and in the various water receptacles about the house. In our own Southern States it very commonly breeds in the above-ground cisterns which are in general use. Often the larvæ are found in flower vases, or even in the little cups of water which are placed under the legs of tables to prevent their being overrun by ants. They have been repeatedly found breeding in the holy water font in churches. In short, they breed in any collection of water in close proximity to the dwellings or gathering places of man. - Normal position of the larvæ of Culex and Anopheles in the water
(a) Normal position of the larvæ of Culex and Anopheles in the water. Culex, left; Anopheles, middle; Culex pupa, right hand figure - The common round-web spider, Epeira vulgaris of Hentz (Under Side)
The body is seen to be divided into two parts, connected only by the narrow joint, A, just behind the last pair of legs. The front half of the body, called the thorax, contains the stomach, the central part of the nervous system, and the large muscles which work the legs and jaws. The hinder half, the abdomen, contains the intestine, the breathing-organs, the principal circulating-vessels, the organs of reproduction, and the spinning-organs. Connected with the thorax are six pairs of limbs, four pairs of legs, B B B B, a pair of palpi, C, and a pair of mandibles, D.