2 Chiasognathus Grantii, under side
3,4 Maxillae with lacinia and palpus
5 Mentumprocesses of labium and palpi, under view
6 Base of anterior femora
7 Mentum, labium, &c. upper view
8 Labium with processes amd palpi, lateral view
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.
Protozoa from the gut of the wood-feeding cockroach Cryptocercus punctulatus.
A, Eucomonympha imla, female above, male below, c. X 375. (From Cleveland [1950c].)
B, Barbulanympha sp. (From Cleveland .)
C, Urinympha talea, c. X 712. (From Cleveland [1951a].)
D, Rhynchonympha tarda, c. X 450. (From Cleveland .)
E, Trichonympha okolona or T. algoa, c. X 390.
Diagram illustrating the relationship between a mature plant of Herpomyces stylopygae and the integument of Blatta orientalis.
Richards and Smith have studied the life history of Herpomyces stylopygae on the oriental cockroach. The plants grow only on living cockroaches, and the infection is disseminated by contact.
Representative Protozoa associated with cockroaches.
A, Monocercomonoides melolonthae, X 3094 (after Grassé).
B, Coelosporidium periplanetae, X 1310 (after Sprague); trophozoite with spores and chromatoid bodies.
C, Endamoeba blattae, X 273 (after Kudo); trophozoite.
D, Lophomonas striata, X 330 (after Kudo).
E, Lophomonas blattarum, X 660 (after Kudo).
F, Retortamonas blattae, X 3094 (after Wenrich).
G, Nyctotherus ovalis, X 175 (after Kudo).
H, Gregarina rhyparobiae, c. X 52: mature trophozoite attached to intestinal wall of Leucophaea maderae. (Redrawn from J. M. Watson .)
I, Diplocystis schneideri, c. X 14.4 (after Kunstler).
J, Gregarina blattarum, c. X 57 (after Kudo).
K, Protomagalhaesia serpentula, X 36 (after Pinto).
L, Gamocystis tenax, magnification not known (after Schneider).
The cockroach mite, Pimeliaphilus podapolipophagus83 visits
(Blatta orientalis). a, female; b, male; c, side view of female; d, young. After Marlatt, Entom. Bull. 4, U.S. Dept. Agric.
The young creature is hatched from the egg in a form closely resembling, on the whole, that of its parent, so that the term 'miniature adult' sometimes applied to it, is not inappropriate. The baby cockroach is known by its flattened body, rounded prothorax, and stiff, jointed tail-feelers or cercopods; the baby grasshopper by its strong, elongate hind-legs, adapted, like those of the adult, for vigorous leaping.
showing proboscis formed by flexible maxillae (g) between the labial palps (p);c, face; e, eye; the structure m has been regarded as the vestige of a mandible. B. Basal part (b) of maxilla removed from head, with vestigial palp (p). Magnified.
a, Diamond-back Moth (Plutella cruciferarum)
b, young caterpillar, dorsal view
c, full-grown caterpillar, dorsal view
d, side view
e, pupa, ventral view.
From Journ. Dept. Agric. Ireland, vol. I
The simple nests and tubes that have been described are made by spiders, most of which spin no other webs. The larger and better known cobwebs for catching insects are made by comparatively few species. On damp mornings in summer the grass-fields are seen to be half covered with flat webs, from an inch or two to a foot in diameter, which are considered by the weatherwise as signs of a fair day. These webs remain on the grass all the time, but only become visible from a distance when the dew settles on them. Figure is a diagram of one of these nests, supposed, for convenience, to be spun between pegs instead of grass. The flat part consists of strong threads from peg to peg, crossed by finer ones, which the spider spins with the long hind-spinnerets
Long-legged, brown spiders, with two spinnerets longer than the others, and extending out behind the body. Figure is Agalena nævia, the common grass spider.
They make flat webs, with a funnel-shaped tube at one side, in which the spider waits.
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.
Body of an insect (Hymenoptera), showing the principal divisions
c, compound eyes
s, simple eyes
1 to 9 segments of the abdomen.
Bird watching a butterfly
Birds chasing insects
A external view
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.
Longitudinal section of Female Cockroach, to show the position of the principal organs.
S.gl, salivary gland
S.r salivary reservoir
St, chylific stomach
Of the uses to which Cockroaches have been put we have little to say. They constitute a popular remedy for dropsy in Russia, and both cockroach-tea and cockroach-pills are known in the medical practice of Philadelphia. Salted Cockroaches are said to have an agreeable flavour which is apparent in certain popular sauces.
A female cockroach, Periplaneta, with the dorsal exoskeleton removed, dissected to show the viscera.
3 antenna, cut short
6 nervous system of crop
8 hepatic caeca
9 mid-gut or mesenteron
10 Malpighian tubules
13 salivary glands
14 salivary receptacle
16 ventral nerve cord with ganglia
20 genital pouch, in which the egg-cocoon is found
21 colleterial glands
22 anal cercus
Mouth appendages of Periplaneta (magnified).
A MandibleB First maxilla
C Right and left second maxillae fused to form the labium
3 ligula, corresponding to the lacinia
4 paraglossa, corresponding to the galea
Periplaneta orientalis, male.
4 anterior wing
5 soft skin between terga and sterna
6 sixth abdominal tergum
7 split portion of tenth abdominal tergum
10 coxa of third leg
Periplaneta orientalis, male
2 palp of first maxilla
4 anterior wings
5 femur of second leg
8 cerci anales
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.
(a) Anterior part of venter
(b) second stage nymph
(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.
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.
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.
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."
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.
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 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.
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.
Of the twenty or more species of this genus occurring in the United States the following are known to bite: C. cinctus, C. guttipennis, C. sanguisuga, C. stellifer, C. variipennis, C. unicolor.
The larvæ are elongate, with the head and thorax sharply distinct. The larval antennæ are prominent, consisting of a single cylindrical and sometimes curved segment. The outer third is often narrower and bears at its base a fan-shaped tuft of hairs, the arrangement and abundance of which is of systematic importance. About the mouth are the so-called rotary mouth brushes, dense masses of long hairs borne by the labrum and having the function of sweeping food into the mouth. The form and arrangement of thoracic, abdominal, and anal tufts of hair vary in different species and present characteristics of value. On either side of the eighth abdominal segment is a patch of scales varying greatly in arrangement and number and of much value in separating species. Respiration is by means of tracheæ which open at the apex of the so-called anal siphon, when it is present. In addition, there are also one or two pairs of tracheal gills which vary much in appearance in different species. On the ventral side of the anal siphon is a double row of flattened, toothed spines whose number and shape are likewise of some value in separating species. They constitute the comb or pecten.
Accessory to the salivary apparatus there is on the ventral side of the head, underneath the pharynx, a peculiar organ which the Germans have called the "Wanzenspritze," or syringe. The accompanying figure of the structure in Fulgora maculata shows its relation to the ducts of the salivary glands and to the beak. It is made up of a dilatation forming the body of the pump, in which there is a chitinous piston. Attached to the piston is a strong retractor muscle. The function of the salivary pump is to suck up the saliva from the salivary ducts and to force it out through the beak.
Freshly hatched larva of Julus multistriatus?
3 mm. long: a, 5 pairs of rudimentary legs, one pair to a segment.
Although Cicadas abound most upon the oaks, yet there seem to be no trees or shrubs that are exempt from their attacks, unless it be the various species of pines and firs. The punctured limbs languish and die soon after the eggs are laid, and as often happens are broken off by the winds; but when this is the case the eggs never hatch, for the moisture of the living branch seems necessary for their proper development.
The eggs are one-twelfth of an inch in length, and one-sixteenth of an inch through the middle, but taper to an obtuse point at each end. They are of a pearl-white color. The shell is so thin and delicate that the form of the inclosed insect can be seen before the egg is hatched. One writer claims that fifty-two days, and others that fourteen days, constitute the period required for the hatching of the egg.
When it bursts the shell the young insect is one-sixteenth of an inch long, and is of a yellowish-white color, excepting the eyes and the claws of the fore-legs, which are reddish. It is clothed with small hairs. In form it is grub-like, larger proportionally than the parent, and provided with six legs, the first pair being very large, shaped like lobster-claws, and armed beneath with strong spines. Little prominences take the place of wings, and under the breast is a long beak for suction. Its movements, after leaving the egg, are very lively, and nearly as quick as some of the ants.
Agalenidæ, as our funnel-web weavers are called, are long-legged, brown spiders, in which the head part of the cephalo-thorax is higher than the thoracic part, and distinctly separated from it by grooves or marks at the sides. The eyes are usually in two rows, but in Agalena the middle eyes of both rows are much higher than the others. The feet have three claws, and the posterior pairs of spinnerets are two-jointed and usually longer than the others. Agalena nævia, the technical name of our Common Grass Spider, abounds in all parts of the United States, but its very commonness is the principal reason why it is so little known except by the trained naturalist, its very familiarity leading the average man and woman to look upon it with contempt.
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.
Adult, Chrysalis-Case, Pupa, Entrances to Burrows and Egg-Nests.
In the winged state Cicada septendecim is of a black color, with transparent wings and wing-covers, the thick anterior edge and veins of which being orange-red. Near the tips of the latter there is a dusky zig-zag line which resembles in shape the letter W. The eyes, when living, are also red, while the legs are a dull orange, which color is conspicuous along the edges of the rings of the body. The wings expand from two and a half to three and a quarter inches.
Mother-Aphis and Her Army of Children on Tube
Whilst engaged some few years ago in the study of the species that affects the blossoms of one of our gourds—the Cucurbita ovifera of botanists—certain phenomena were observed, which promised an easy and speedy solution of the problem.
Gathered in compact masses, like companies of soldiery preparing for a foray, hundreds of aphides were seen, busily feeding, all over the flowers. There were old and young, not an indiscriminate mingling of ages and sizes, but an orderly arrangement of families, each family preceded by its own appropriate head. First came the very young of each family, only to be followed by those that were older, leaving the oldest of all to lead up the rear.
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.
His Curious and Unique Method of Defence.
But it is not so much his odd shape as a most extraordinary property he possesses, which is singularly unique in the animal kingdom, that makes him an object of interest and curiosity. Deep down in his most marvellous body a fluid, highly volatile in its nature, is elaborated, which the little creature can retain or expel at his pleasure. It is only, however, when alarmed that he utilizes this fluid in small quantities in defense, but its effect is wonderful, for in coming into contact with the atmosphere it immediately volatilizes and explodes, looking very much like a discharge of powder from a miniature artillery. In consequence of this phenomenon the insect which produces it is popularly called the Bombardier Beetle.
Larvæ in Burrows. Two Other Species in Background.
They are true children of the earth. The eggs are laid in the earth, and in the earth the grubs are hatched, and in the earth they spend their days, and in the earth they prepare their shrouds, and, wrapped therein, sleep their pupa-sleep through the long, dreary winter, and with the returning warmth of spring crawl out of their earthy chambers to run and sport on earth, seldom using their new-formed wings to fly away from their beloved mother.
Neuters About Their Work.
It was on an occasion while exploring a neighboring thicket for the objects of his search, that he discovered, underneath a large flat stone which he had raised, a nest of a small red ant, which he took to be the Lasius flavus of the books. The ground was covered all over with pits, and divers communicating roads, and round about were hundreds of ants, larvæ in various stages of development, pupæ and eggs, and innumerous flocks of a white aphis, all of which were being tenderly cared for by a large army of thoughtful nurses.
Larva on Branch Below, and Cocoon on Twig Just Above.
No insect affords a better proof of high art in nature, and of the transcendent beauty of the Creator’s thoughts, than the Luna moth, which is as preëminent above her fellows as her namesake, the fair empress of the sky, above the lesser lights that dominate the night. Her elegant robes of green, set off with trimmings of purple, and jewelled with diamonds, added to her queenly grace and personal charms, will always distinguish her from the profanum vulgus of the articulata.
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.