Part 11

The =Wheat-haulm Moth= (_Luperina didyma_).

_Moth_: Span of wing 1⅕ inches. Individual specimens differ very much from one another: brownish, greyish yellow to ochre yellow, with various dark and light markings. _Caterpillar_: With sixteen legs, and over an inch long in full-grown specimens (May); thin, spindle-shaped; stiff; bright shining green, with two broad dark red lines on the back. The caterpillars live in the stalks of wheat plants, and other gramineous forms, hollowing them out; they hybernate when tolerably young. In spring they continue to hollow out the wheat plants, going from one stalk to another. The plants attacked quickly have their leaves turned to a rusty colour, and they sicken or even die.

The =Grass Moth= (_Charæas graminis_).

_Moth_: Length ⅗ of an inch; span of wings about 1⅓ inches. Antennæ of the male comb-like. Fore wings short, of a brownish-red, olive brown, or dirty olive-green ground colour, with three whitish patches, and darker markings. Hind wings yellowish grey, brighter at the roots. _Caterpillar_: With sixteen legs; 1⅘ inches long; bronze grey, back more of a bronze brown, with three narrow bright longitudinal streaks. Head ochre yellow. The moth lays her some two hundred eggs during July, in little heaps at the bases of the grass haulms and leaves. The caterpillars hide during the day, and feed at night. They are very injurious even in the autumn, but become insatiable the following spring, always devouring the lowest parts of the haulms and leaves, so that the upper parts die off. They wander in large companies from one field to another. In June they become pupæ of a shining reddish brown below the surface of the soil or under sods. _Enemies_: swine, moles, shrews, rooks, wagtails, ducks, fowls. _Remedy_: Driving in swine, where this is practicable.

[Illustration:

FIG. 101.—The Grass Moth (_Charæas graminis_) and its caterpillar. ]

The =Darnel Moth= (_Neuronia popularis_).

_Moth_: Length rather less than ⅘ of an inch; span of wings nearly 1⅗ inches. Much variegated, beautiful. Fore legs reddish brown, with peach-coloured glow; all the nerves and several markings yellowish white, and dark markings as well. Hind wings yellowish, and abdomen white. Head and thorax brown, mixed with yellowish white. _Caterpillar_: Over two inches long, and about one-third of an inch thick; 16-legged; tapers at both ends. Has an oily lustre. Dorsal side of a bronze brown, sharply marked off by a yellowish line from the bright brownish grey ventral side, and traversed by three longitudinal bright brown lines, which in young specimens are almost white. Habits pretty much like those of the preceding species.

The =Silver Y Moth= (_Plusia gamma_).

[Illustration:

FIG. 102.—The Silver Y Moth (_Plusia gamma_), with caterpillar and pupa. ]

_Moth_: About ⅝ of an inch long; span of wings 1¾ inches. Dark grey, mixed with a reddish tint, and darkly marbled. About the middle of the fore wing there is a very obvious gamma (γ), or Y-shaped mark. Hind wings bright brown at the root, darker at the margins, with a whitish fringe. A crest of hairs on the dorsal side of the thorax. _Caterpillar_: 12-legged. It bends its body like a looper (Fig. 102). Length 1 to 1⅕ inches. Ground colour green; but there may be variations in this from a dirty green to a brownish colour. Six fine longitudinal lines on the back, and a yellowish line above the legs. The caterpillar is almost naked, only possessing a few small, isolated bristle-like hairs. _Habits_: At least two generations, and sometimes as many as five in two years. The Silver Y Moth generally hybernates as a half-grown caterpillar, but sometimes also in the pupa, or moth state. The caterpillars may therefore be met with the whole year; but they are usually most abundant from the end of June to the middle of August, and, under favourable conditions, may become an agricultural pest. They devour the leaves of almost all wild and cultivated plants (except grasses, corn, and trees), and are especially fond of leguminous plants (peas, vetches, clover), flax, beet, rape, cabbage, and buckwheat. The moths mostly appear in May, but also in July, and later on in the summer, especially on clear days. The female lays her numerous bright green eggs, some four hundred in number, separately, on the leaves of the above-named plants. The caterpillars are not always easy to see, owing to their greenish colour; under favourable conditions they may pass through the whole of their development up to the moth stage in from six to seven weeks. In some years they appear in such large numbers, that almost all the cultivated plants found in the fields of an infested region are utterly spoilt by them, excepting the corn. _Natural enemies_: Starlings, all sharp-beaked singing birds haunting fields; sparrows; ground beetles, rove beetles, and the larvæ of these families; several ichneumon flies, parasitic fungi. _Remedies_: Driving in poultry, where practicable. Collecting, _e.g._ by means of a machine invented by L. Dehoff, of Gutenberg, near Halle. “Several troughs with steep inner walls are fastened together by laths, at distances equal to those between adjacent furrows, and besoms are fixed to the laths. These troughs are drawn along like sledges by a horse walking in the furrows, and the caterpillars are swept by the besoms into the troughs, from which they are collected in sacks at the ends of the furrows. With this cheap machine about twelve acres per day can be cleared” (Taschenberg).

Family: =Pyralidæ= (_Snout Moths_).

Small moths with thread-like antennæ, comb-like in the males of a few species, with tolerably large eyes, and very large labial palps often stretched out in front like a beak (Fig. 103). Fore wings of an elongated triangular shape. Wing booklets. Legs tolerably long. Caterpillars slightly hairy, with four or five pairs of pro-legs.

The =Rye Snout Moth= (_Pyralis secalis_).

_Moth_: ⅗ of an inch long, span of wings 1⅕ inches. Wings elongated, whitish grey, with an A-shaped patch on the fore wings. _Caterpillar_: Rather more than ⅖ of an inch long; green, streaked with brown, 16-legged, with a brown head, and tapering at both ends. _Habits_: The caterpillar lives during June in the rye haulms, hollowing them out. As a result of this, the ears remain hidden between the leaves and leaf-sheaths, and it often happens that only the tips of the awns appear externally. No grain is formed; the ears first become white and dry, and then fall off.

The =Hop Snout Moth= (_Hypena rostralis_).

[Illustration:

FIG. 103.—The Hop Snout Moth (_Hypena rostralis_). ]

_Moth_ (Fig. 103): Length rather less than ⅖ of an inch; span of wings 1⅕ inches, or more. Fore wings usually brownish, somewhat scalloped on the fringed outer margins; a zigzag black line near the base; in the middle, near the front edge, a patch bordered with white, and behind this a dark longitudinal streak. Hind wings dull grey, with a silky sheen. _Caterpillar_: At most one inch long, 14-legged, very slender, green, with a dark middle line and two white side lines. Very active; wriggles about on the ground like an eel. _Habits_: The moth is on the wing at the beginning of August, the second generation in August; the latter hybernates in outhouses, barns, summer-houses, etc. The eggs are laid on wild and cultivated hops, also on stinging nettles. The caterpillars are found on the hop plants, especially in June; they sometimes entirely devour the leaves, with the exception of the nerves. In July they become pupæ, either between the leaves or on the soil, and are invested in a grey cocoon. The moths appear at the beginning of August, and give rise to a second generation of caterpillars, from which, after the pupa stage, the moths which live through the winter are developed.

The =Cabbage Snout Moth= (_Botys forficalis_).

_Moth_: Length about half an inch. Span of wings rather over one inch. Fore wings sharply bent in front before their sharp tips; rusty yellow, somewhat darker on the nerves, with rusty brown transverse streaks from the outermost corners to the middle of the hinder margin, and with other reddish brown markings. Hind wings and body shining straw yellow. _Caterpillar_: ⅘ inch long, 16-legged, tapering in front and behind. Yellowish green, with indistinct longitudinal lines and bright brown head. A few small yellowish-green hairs. _Habits_: The first generation appear in small numbers in May. The caterpillars hatched out from the eggs of these live (May and June) on the leaves of cabbages and wild cruciferous plants. They always shelter themselves between the leaves, and spin a few thin threads across the entrances to their abodes. The caterpillars burrow horizontally in the earth, and there become pupæ invested in cocoons. The moths of the second generation appear in August; in autumn the caterpillars hatched from their eggs damage cabbages, sometimes to a large extent. In October they burrow into the soil, where they hybernate. _Remedy_: Deep digging or ploughing after the crop, by which the larvæ invested in webs are buried deeply, and consequently for the most part killed.

The =Mother-of-pearl Moth= (_Botys margaritalis_ = _B. extimalis_).

_Moth_ (Fig. 104): Length nearly ⅖ inch; span of wing over 1⅕ inches. Fore wings bright sulphur yellow, with large rust-coloured patches, and two rusty yellow transverse lines. Hind wings shining straw yellow; all four wings with a mother-of-pearl sheen. _Caterpillar_ (Fig. 104): ⅘ inch, 16-legged, yellowish, head and neck-shield black. Body with a broad, grey, longitudinal streak on each side. Four longitudinal rows of dark brown warts. _Habits_: The moth is on the wing in June and July, and lays the longish ovoid eggs on cruciferous plants (rape, radish, several wild forms). The caterpillar lives concealed in a white web, and gnaws holes in the pods, into which it inserts the forepart of its body for the purpose of devouring the still green seeds. The attacked pods, owing to the presence of round holes in them, look something like flutes or fifes.

[Illustration:

FIG. 104.—The Mother-of-pearl Moth (_Botys margaritalis_), with larva (1) and injured pods. ]

The full-grown caterpillars burrow into the soil, where they hybernate in a delicate web. _Remedy_: Compare the preceding species.

Family: =Tortricidæ= (_Leaf-rollers_).

Small, thick-set moths (Fig. 105), with smaller palps than the snout moths. Fore wings broad at the root, with straight or somewhat curved outer margins. Hind wings as broad, or even broader, than the fore wings. When at rest the fore wings lie in a roof-like way. They usually possess many characteristic markings. Hind wings greyish, without markings. Antennæ thread-like. Caterpillars hairless, or only slightly hairy; 16-legged: many kinds live in leaves, which they roll up; others in twigs, buds, and fruits, which they hollow out.

The =Fawn-coloured Pea Moth= (_Grapholitha nebritana_ = _G. pisana_).

_Moth_ (Fig. 105): Length ⅜ inch; span of wings about ⅖ inch. Fore wings fawn-coloured, with metallic sheen; alternating short, white, and dark lines on the front margin. Hind wings black, with bronze sheen and white fringe. _Caterpillar_: ⅓ inch long; 16-legged; pale green, with brown or black head, neck-shield, and last body segment. The thoracic legs are black. Dark warts on each segment. _Habits_: Compare the succeeding species.

[Illustration:

FIG. 105.—The Fawn-coloured Pea Moth (_Grapholitha nebritana_). ]

The =Crescent Pea Moth= (_Grapholitha dorsana_).

_Moth_: Somewhat larger than the preceding species. Fore wings olive brown, with many small short white lines on the front margin. A yellowish white crescent on the middle of the hinder margin. Hind wings brownish. _Caterpillar_: Nearly ⅖ inch long, 16-legged, orange yellow, with brown or black head, neck-shield, last body segment, and thoracic feet. Covered with brownish-yellow warts. _Habits_: The moths fly about in large numbers round the pea blossoms, always a short time after sunset. The female lays one, two, or at most three eggs, on a very young pod, or on an ovary. In fourteen days the caterpillar is hatched, bores into the pod, and attacks the peas. The opening made in the margin of the pod closes up again. The pod generally ripens early. When it opens, the full-grown caterpillars creep out, and become pupæ in the soil, within a web, where the pupa lives through the winter. The peas attacked are always covered, while in the pod, with the coarse-grained excrement of the caterpillars, and are often united two or three together by web fibres. _Remedy_: Deep digging of the soil before the winter, or, still better, deep hoeing as soon as the pea crop is gathered in. In this way many of the caterpillars or pupæ hidden in the soil will be destroyed.

Family: =Tineidæ= (_Leaf-miners_).

[Illustration:

FIG. 106.—The Larch Moth (_Coleophora laricella_). ]

These moths are the smallest of the Lepidoptera. Like the snout moths, they have strongly developed labial palps, but are distinguished from them by their small wings; the hind wings are especially small, and have sharp tips. The extent of the wings is increased by a broad marginal fringe. When at rest, the wings slope like a roof, and the fringe near their tips is often turned upwards. Antennæ thread-like, tolerably long—in the males of a few species may even be very long. Caterpillars slightly hairy, with five, or, rarely, four pairs of pro-legs. To this family belong the well-known =Clothes Moth=; the =Corn Moth=, living in stored-up grain; and also—

The =Carrot Moth= (_Depressaria nervosa_ = _Hæmylis daucella_).

_Moth_: Length ⅖ inch. Span of wings rather over ⅘ inch. Fore wings reddish-grey brown, blackish on the nerves, and with scattered whitish markings. Hind wings more of a grey brown. Thorax and abdomen very shiny, and somewhat brighter than the wings. _Caterpillar_: Nearly ⅖ inch long, tolerably thick, especially in the middle, and variegated. Head, thorax, and last body segment shining black, the last two regions with reddish-yellow margin, and the thorax, in addition to this, divided into right and left halves by a longitudinal yellow line. The rest of the body is olive green; a broad orange-coloured line divides it into a darker dorsal and a lighter ventral side. On the back many ill-defined warts of a shining black colour. _Habits_: In March and April many of the carrot moths which have survived the winter come out of their hiding-places; they only fly at night. The eggs are laid separately on umbelliferous weeds, carraway, or carrot plants. The caterpillars are first seen when the plants flower; they live on the flower-stalks, which they bind together by a few threads, and devour the flowers and young fruits, sometimes even the flower-stalks. The caterpillars are very active, and let themselves down by a thread when disturbed. Usually they are fully grown in five weeks, and then bore into the stalks of the plant, where they become pupæ. It is not known whether there are one or two generations. The caterpillars are found at very various times, from May to August.

The =Diamond-back Moth= (_Plutella cruciferarum_ = _Tinea xylostella_).

_Moth_: About ¼ inch long; span of wings ⅗ inch. Fore wings small, lancet-shaped, with long fringes. Ground colour yellowish brown, darkly speckled. Hind wings brownish grey, small, strongly fringed. When at rest the long fringes form a sharp backward and upwardly directed comb, while the antennæ are applied together and stretched straight forwards. _Caterpillar_: About ¼ inch long, tapering in front and behind. A beautiful green, with a black head. Lives hidden under a very thin web or under a few fibres, on the lower side of the leaves of cabbage, rape, and other crucifers. _Habits_: The pupa lives through the winter; the moths emerge in May, and fly about in the evening. Two generations; the first generation of caterpillars in the first half of July, the second in late summer. The second generation is particularly apt to be destructive to cabbage. Pupæ found on the leaves of the plants attacked, and surrounded by a thick web.

SIXTH ORDER: Hemiptera (HALF-WINGED INSECTS).

[Illustration:

FIG. 107.—Left pair of wings of a Bug. ]

The mouth-parts are modified into a sucking and piercing beak. Head small. Legs usually slender, with two- or three-jointed feet. Wings are absent in several species (_e.g._ bed bugs); in one section (_e.g._ fruit bugs) the fore wings are half of leathery, half of membranous texture (Fig. 107); in others, all four wings are membranous (winged plant lice), or the fore wings are somewhat harder than the hind wings (frog-hoppers). Incomplete metamorphosis (p. 89). None of agricultural importance except—

Family: =Aphidæ= (_Plant Lice_).

[Illustration:

FIG. 108.—The Bean Aphis (_Aphis papaveris_); a larva of the same below. ]

Long, five- to seven-jointed antennæ. Long thin legs, no power of springing. Sucking beak long and thin. In the same species there are both winged and wingless aphides, mostly the latter. In autumn, male and female specimens are found. After pairing, the latter lay their eggs, which are destined to live through the winter. The aphides hatched from these the following spring are all females, but are distinguished from those of the previous autumn by producing living young, which contain at the time of their birth the germs of a new generation. The number of young produced by a single female, and the number of generations appearing within the year, vary according to the species. There are species in which each female bears from eighty to one hundred young, and nine to sixteen generations succeed one another in the year. In autumn males and egg-laying females once more appear. As a rule the eggs live through the winter, but the insects themselves may also do this. I must add that there are constant differences within the boundaries of the same species according to the habitat, and especially in the species which regularly wander, either from one plant to another, or from the leaves to the roots. But since the species injurious to agriculture do not migrate in this way, nothing further need be said on the point. As aphides suck plant juices during the whole of their lives, and have enormous reproductive powers, they are very destructive. They suck from stems and leaves the juices which would otherwise be used by the plants themselves for growth or for the production of flowers and fruit, and bear young, which bore their beaks into the same part in the immediate neighbourhood of their mother, and quickly begin to multiply in their turn. In this way, colonies consisting of a hundred or more individuals are regularly formed (_e.g._ on peas, beans, roses). A plant part attacked in this way shrivels for want of nourishment, and the aphides upon it would die if they did not wander elsewhere. The third generation usually contains, not only wingless individuals, but also others which, after repeated moults, fly away and start a new colony in another plant. Since aphides have many enemies (starlings, sparrows, grasshopper warblers, etc., lady-birds and their larvæ, drone fly larvæ, lace fly larvæ), and are often killed in large numbers by wind and rain, it only occasionally happens, particularly in dry summers, that they entirely or largely destroy the plants they infest. They injure plants, not only by drawing away their nourishment, but also by the separation of a sugary sticky fluid from the anus. If the minute drops of this fluid fall from the upper parts of an infested plant to the lower (garden and field beans), or from the leaves of an infested tree to the plants growing at its foot, or, as sometimes happens, are carried by the wind to more distant plants, great damage may be caused. The fluid evaporates and leaves behind a shining sticky substance, which closes up the stomata of the leaves, and partially checks exchange of gases (assimilation and respiration). Particles of dust, sand, and smoke carried by the wind, and also the cast skins of the aphides, stick to the surface of the leaves and render exchange of gases still more difficult. The leaves develop brown dirty patches, and die off. Besides this, the spores of disease-producing fungi, carried by the wind, stick very easily to the places covered by the sweet fluid, and readily germinate in it. Aphides may thus be the indirect cause of several diseases (_e.g._ smut). These insects are destructive, therefore, to other plants than those infested by them. _Remedies_: Spraying with any one of the fluids destructive to them—soapy water; a decoction of quassia chips; tobacco water, not too concentrated; Nessler’s fluid (1½ ozs. soft soap, 2¼ ozs. tobacco mixture, 2 ozs. fusel alcohol, half a pint ordinary alcohol, diluted with rain water up to a quart: when used, mix with one-fifth the quantity of rain water); Koch’s fluid (2 lbs. soft soap dissolved in half a gallon of hot water; ½ lb. of quassia chips extracted for twelve hours in 5 quarts of rain water, and the fluid thus obtained boiled and filtered. It is then added to the soap water, and the whole brought up to 10 gallons by addition of rain water). Spraying with one of the above-named fluids must be renewed in a short time, so as to reach all the aphides wherever possible; if even a few remain untouched, there will soon be a large number again. A warm evening is best for the spraying. Infested plants can also be strewn with finely powdered substances, or these may be scattered over them by means of a small bellows. Since such substances should remain on as long as possible, they should be used after rain or early in the morning, when the dew is still on the leaves. Among powdered matters suitable for the purpose, the following may be named: gypsum, lime, tobacco, wood-ash, insect powder (prepared from the flower-heads of Persian species of chrysanthemum and from tansy heads). It must also be pointed out, that these remedies must be employed as soon as the insects begin to show themselves in considerable numbers; it is not desirable to delay till the infestation has made considerable headway, as it is then much more difficult to get a satisfactory result. In some cases, it is desirable to cut off and burn or otherwise destroy much infested parts, or those parts on which the insects first begin to multiply (_e.g._ early cutting off of the tips of the stems in field and garden beans).

The species of aphis which most commonly occur upon cultivated plants are:—The =Bean Aphis= (_Aphis papaveris_), ¹⁄₁₂ inch, black; on the tips of the stems of field and marsh beans, also on poppy, turnips, lettuce, and on several wild composites and umbellifers. The =Pea Aphis= (_Aphis ulmariæ_), ⅛ to ⅙ of an inch long; green; July to September on peas, chickling peas, and several wild leguminous plants; very destructive. The =Corn Aphis= (_Aphis cerealis_), ¹⁄₁₂ inch, green or reddish brown, also reddish brown with green abdomen; June to August on rye, barley, oats and several grasses; sucks the axis of the ears, and the flower-stalks; as the (black) eggs remain on the stubble during the winter, it is advisable to plough this deeply in immediately after harvest. The =Oat Aphis= (_Aphis avenæ_), ¹⁄₁₂ inch, dark green, speckled with white; on oats and barley, scarcely ever on the ears, but on the leaf-sheaths and the upper sides of the rolled-up leaves. The =Hop Aphis= (_Aphis humuli_), ¹⁄₁₂ inch, green; on the under side of the hop leaves, and, when very abundant, on the scales of the fruit. The =Cabbage Aphis= (_Aphis brassicæ_), ¹⁄₁₂ inch, dark green, speckled with grey; from May to September on all kinds of cabbage, and also on other crucifers.

SEVENTH ORDER: =Physopoda= (BLADDER-FOOTED INSECTS).