Rensselaer Union and Jasper Republican, Volume 8, Number 23, Rensselaer, Jasper County, 24 February 1876 — Insect Pests Among Farm Stock. [ARTICLE]

Insect Pests Among Farm Stock.

Notwithstanding all that has been written about insects which are especially infurious to our domesticated animals, there s still a large class of farmers who have no idea of the number of species, or their differentliabits. Of course we can only briefly touch upon this subject at the present time, as it would require volumes to give a still history of all the Insects which annoy pr inflict direct punishment upon oUr farm sto£k; hence we will only attempt the naming of a few of those best known and most common. We are prompted to do this by the many letters received of lute from subscribers, who ask for information in regard to certain diseases caused by parasitic insects. But before proceeding to name them we desire to give the reader one simple lesson in entomology, if he has not already learned it. Insects during their lives are subject to great changes or transformations, and assume very different forms, in what are termed their different stages of The four principal ones are these: First, the egg is deposited by the female; from this egg comes the grubworm, ca erpillar, or whatever common name is applied, but scientifically it is a larva; hence we speak of the grub, or caterpillar, stage of existence in an insect as the “ larval stage.” These lame, or grubs, grow from the time of batching Irom the egg, if no accident happens to them, unul they reach maturity; then comes the third change,or transformation, and the larva becomes pupa, which is also called the quiescent stage, inasmuch as the pupa partakes of no food, and has

very restricted; powers of motipn. These pupte are sometimes naked, as In of some kinds of butterflies, and are called “chrysalids,” while others are enclosed in a thick outer envelope called a cocoon, like that of the common silk worm; but whatever be the outward form, assumed, they are all said to be in the pupal stage. The fourth change is the bunting open pf the pupal envelope and the nmerglug ol the perfect insect, or, as technically termed, imago. The common house-fly and the mosquito, os well aft the larger butterflies, moths and beetles, all undergo these four transformations, or metamorphoses ; therefore it can be readily understood how an insect may be injurious to plants or animals in one stage of its existence, and not so in another. TUK OX BOT FLY. This insect Is also called gad fly, although the latter more proper]y,belongs to those species of flies which annoy stock by puncturing the skin for the purpose or socking the blood. The botflies, on the contrary, do not injure animals in their imago, or perfect state, bill It is their larv® which are directly Injurious. The ox hot fly (csstrus bovis) is a large and handsomely colored insect, which appears during the summer, the femtklfe depositing her eggs upon the backs of cattle where they soon hatch, and die larv® or grubs ' penetrate the flesh, causing small tumors and sores. The grubs feea upon the flesh of the animals, and grow until they arc nearly or quite an inch long, and during the fall or early part of winter they cease feeding, and are transformed Into pupce, the latter remaining in the tumors during winter, and the imago or perfect fly emerging in spring. These pup® of the ox hot iiy are what several of our subscribers have referred to of late under the name of “wolf” in cattle, a rather singular name to apply to a fly in one stage of its existence; out there is no accounting for the vulgar local names of such tbipgs, and “wolf” seems to be a favorite among farmers. The larv® of a little grain weevil which is found in barns is called “wolf,” and the imaginary disease which is supposed to cause cows’ tails to become then we have “wolf teem” m colts, another imaginary disease or cause of blindness —in fact, this wolf is a terrible creature, turning up in various forms, or whenever the farmer neglects to take proper care of his stock. The ox hot fly attacks young stock more frequently than old, and we presume the same instinct which guides the female fly to deposit her eggs upon the back, where she can do it with greater safety to herself than on other parts of the body, also leads her to young animals whose caudal appendage is not sufficiently developed to be a very formidable weapon in warding off such enemies. Those farmers who may think the long hairs on their cows’ tails of no particular use except to switch the milkmaid in the lace, or flop into the milk-pail during the process of milking, would do well to watch “ old bos” in one of her battles with hot and other kinds of annoying species of flies, and see how skillfully she uses the weapons nature has provided for this purpose. Cattle will also resort to bushes in order to rid themselves of these pests, and rub their backs against the lower branches of trees to kill the eggs and young, newly-hatched grubs if such means of defense are provided. But there are thousands of. farmers who will neither permit shade or shelter for their stock, assuming to know what is best for their health and comfort, although the poor, sickly, worm-eaten animals are fearful witnesses against such presumption. Tpx HORSE BOT FLY. The female of this fly is well known to most farmers, as she is usually seen darting about the legs of horses in summer, her long slender abdomen curved upward while seeking a place to deposit an egg. The eggs are generally deposited upon the hairs or the rore legs, where they can be most readily reached by the animal’s lips, instinct teaching the insect that if they were deposited upon the hairs of the tall, hind legs, or back, few if any would ever reach their destination, which is the horse’s stomach, where they become what are known as bots. The eggs remain attached to the hairs, and the grubs hatch in about twenty days, but do not leave the shell until the horse, happens to lick or bite his legs, and thus ttie larv® are afforded an opportunity of leaving the hairs and are conveyed into the animal’s stomach, where they find both the food and heat necessary for their wants. Here they remain attached to the inner membrane of the stomach until the period arrives for them to become pup®, when they let go their hold, pass through the intestinal canal, and are deposited in the manure heap or elsewhere. It is claimed by some authors that the larva passes the animal and spends its pupa stage in the grpuud. But we have frequently found pup® in an advanced stage in the freshly dropped excrement; hence tliere may be some variations in the time ot the appearance of the insect in the outer world.

A PREVENTIVE, All that is necessary to prevent horses being troubled with hots is to keep their hair clear*of hot eggs. This is readily done by scraping them off with a knife, or washing with some liquid that; will soften the giue-like substance by which they are attached to the hairs. THE SHEEP BOT PLY. This is a much smaller species than those infecting the ox or horse, but none the less formidable or injurious. The female, like some other kinds of flies, retains her eggs in the oviduct until they hatch; at least she has been known to do so, and instead of depositing eggs on the nostrils of sheep, lays there minute maggots, which immediately crawl upward. These larvae or maggots remain within the nostrils nearly or quite a year, and canse great inflammation, resulting in & disease known by farmers as “ grub in the head.” During the “ fly season” it would be well to frequently, examine the sheep and remove the maggots before they have ascended out of reach. We might continue these brief sketches of the habits of insects injurious to animals, almost without limit, but the above will suffice to show our readers that the origin of a few of the diseases affecting farm stock is not entirely enveloped in mystery. —N. Y. Sun.