Angelica could have wished that her instructions had been a little more explicit; that her mysterious husband had said something more definite about himself, about the wrongs even to which he alluded, that he had given his reasons for secrecy. She was vaguely excited, vaguely disappointed, provoked, bewildered. She knew not what to think, as she turned this piece of paper in her hand. Her eyes filled with tears-heavy, burning that fell upon the letter, which, to tell the truth, had cost its writer many a struggle, for the count was not handy with his pen. tears From The Popular Science Review. THE COLORADO POTATO-BEETLE. BY W. S. DALLAS, F.L.S. IN ancient times men noted especially the injuries done to their property by their larger and more powerful enemies. It was the boar that came out of the wood to lay waste the vineyard, and the wild beasts of the field that ruined the hopes of the husbandman. At the present day, in all civilized communities, the number of such destroyers is greatly limited; but on the other hand we are compelled to recognize a multitude of mainute enemies, which make up for their smallness by their great abundance, and perhaps are all the more mischievous by reason of their individual insignificance. Among the foes of the agriculturist which have come into notice of late As the evening went on the sisters years, the insect which has been called gathered round Alethea's instrument, and the "Colorado potato-bug," has not only Angel joined in the chorus they were attracted a good deal of attention in practising. They all listened, with ex-America, where it has inflicted serious pressive looks of admiration, to her beau-injury on the potato-crops, but has also tiful voice. At one time she had seriously raised considerable apprehensions on thought of making music her profession. this side of the Atlantic; circumstances Her voice was lovely, and her method was excellent. Poor little thing, crying in the twilight! The tears relieved her heart, until she dried them to the sound of one of the summoning bells. which may justify us in giving some account of its appearance and natural history. This beetle was discovered by Messrs. Say and Nuttall during an early American exploring expedition in what was then known as the "Far West," on the banks of the Upper Missouri, towards the foot of the Rocky Mountains. It was described by Say in the third volume of the "Proceedings" of the Academy of Natural Sciences of Philadelphia, published in 1824, under the name of Dory They made her sing by herself when their chorus was ended, and she tried to remember some of the peasant songs from her native Coire. There was one upspringing melody, with wild, sweet wings (so it seemed to Miss Dosie, who was listening in the window). The music seemed to carry them all away into some distant life, to bring the wide rural freshness of natural things into the shining little English parlour; to bring the breath of wild thyme, the rush of streams, thephora 10-lineata. For many years afterpeace and uplifting of nature upon them all, still bound in their prim conventional order. Angelica's own heart was eased as she sang. She herself seemed to be suddenly convinced. It was a resurrection of hope, of reality, striking into this harmony of sound, and expressing the sympathy of all true souls. The notes met, embraced with heart's gladness, struck their chord, and died away from all their ears. wards nothing was known of it except that such a beetle did exist, its true home being among the Rocky Mountains, where it feeds upon a wild solanaceous plant (Solanum rostratum, Dunal) peculiar to that region. But during all this time the advance of a civilized population was going on with astonishing rapidity in the direction of the Rocky Mountains, converting the vast region west of the Mississippi — which in 1824 Miss Jinny had been laughing and cry- was still a wilderness inhabited only by ing in her corner. When Angelica fin- Indians and hunters into a more or ished she rushed up and kissed her vehe-less settled and cultivated tract, and the mently, saying, "You are a dear crea ture ! settlement of the territory of Nebraska we may with some justice assume that it | diana, Mr. B. D. Walsh estimated the found in the cultivated potato a nourish- rate of its advance at about sixty miles a ment better adapted to its wants than year, and upon this foundation predicted that furnished by the native plant on that it would reach the Atlantic coast which it had previously fed; for it seems about 1878. The insect has contrived by to have set out almost immediately in some means considerably to outstrip the the direction of the more highly culti- prediction, and between 1871 and 1873, vated districts, and spread eastward with at any rate, it must have passed over great rapidity. nearly three hundred miles of country. This astonishing rate of progress can hardly be due to the insect's own exer rapidity with which it appears to be spreading in the densely populated eastern states must be owing to the increased traffic in these districts offering additional facilities of artificial transport. ten most fully upon this beetle, Messrs. Walsh and Riley, remark especially upon this point; and the former compares the advance of the insects through Illinois to that of General Sherman's army in the late war, and says that "the southern columns of the grand army lag far behind the northern columns." In the year 1859 it was still far west, being then at a distance of one hundred miles west of Omaha City, in Nebraska;tions, and it seems probable that the but within two years (in 1861) it reached the state of Iowa, over which it spread completely in about three years, and in 1864 and 1865 did great mischief to the crops. During these years the beetles were also very destructive in the state A striking point in the history of this of Missouri, and in 1864 and 1865 they unwelcome occupation of the cultivated crossed the Mississippi and invaded Illi- low grounds of North America by a nois in great force, causing much injury mountain beetle is that it has taken alto the potatoes in the north-western part most a direct easterly route across the of that state. A branch migration north-continent, and that its advance has been wards commenced in 1862, when the bee-at all times more rapid in the northern tle made a settlement in the south-west than in the southern districts. The corner of Wisconsin; by 1866 it had American entomologists who have writspread over the whole state. During the next two years it completed its occupation of Illinois, and in 1867 passed thence into Indiana and the south-west angle of Michigan, where it was very abundant in 1868. In this year its presence was noted in Pennsylvania, but it was not until 1871 that the Quaker State was fairly invaded by the western beetle. In this year the beetles swarmed about Detroit, at the south-eastern angle of Wisconsin, and great numbers of them are said to have been carried down with floating rubbish and on board ship into Lake Erie, to be wafted along that sheet of water and landed on the Canadian shores, and on the shores of New York and Pennsylvania at the opposite end of the lake. In 1871 also it was reported as doing mischief to the potatoes in Ohio; and in 1873 it had crossed Pennsylvania and reached the District of Columbia, near Washington, and almost to the shores of the Atlantic near Baltimore. In the mean time the northern migration had carried the pest through Wisconsin into Minnesota and Dakota; and through Michigan into Canada, where it made its appearance in 1870. Its transportation into Canada was in part effected by means of the shipping on the lakes. In the south also Kentucky and Western Virginia were invaded in 1871 and 1873. In the year 1868, when the western potato-beetle had reached the centre of In According to Mr. Riley this peculiarity is to be accounted for by the supposition that the western potato-bug being essentially an alpine species, thrives best and therefore spreads most rapidly in the cooler northern regions, and this view is borne out by the fact that even in the north a very hot summer destroys the insect. Of the actual extent of damage done to the potato-crops in the districts which have been visited by these destructive insects we have no precise information, the only approach to an estimate being that of Mr. Walsh, who stated the prob able loss by this cause in a small district at about 1,750,000 dollars. From the nature of the case, it is perhaps almost impossible to arrive at any exact computation. Nevertheless, the statistics published annually by the United States Department of Agriculture seem to indicate a falling off in the potato-crops, which may be due to the ravages of the Doryphora. Thus, the total production of potatoes in all parts of the United States was as follows: Bushels. Acres. Average per Acre. I stated, was described in 1824 by Thomas In 1868 106,090,000 from 1,131,552 66 94 Bushels. In 1869 133,886,000 64 1,222,250 66 109 1-2 66 1,325,119 46 Say as belonging to the genus Dɔryphora ("spear-bearer "), in which the mesoand meta- sterna are produced forward The year 1869 seems to have been an into a spine; this is the origin of the name exceptionally favourable one for the of the "ten-lined spearman "given to the growth of potatoes in all parts of the insect by Mr. B. D. Walsh. The genus Union. Indeed, in Michigan, which had Doryphora has been considerably subdialready been invaded by the Colorado vided by recent authors, and by some beetle, the yield reached the enormous entomologists the species under notice is average of 155 bushels per acre. But referred either to the genus Polygramma when we examine the production of the of Chevrolat or to Leptinotarsa of Stal, individual states, taking some in which in which the sternum is unarmed; but the western potato-beetle had made its it will be sufficient for our present purappearance in force in the above years, pose to speak of it under the old name of and others which had either remained Doryphora decem-lineata. uninvaded or been only partially attacked The perfect beetle measures from twoat the same time, we get the following as fifths to half an inch in length, of an obthe average produce per acre in bush-long-ovate form, and of a tawny or yel els: New Hampshire Pennsylvania New York Missouri Illinois Ohio Michigan 1869. 1870. 1872. lowish-cream colour, adorned with numerous black spots and stripes. Of the former, a very peculiar group, consisting generally of eighteen, occupies the upper surface of the prothorax, or segment immediately behind the head. These consist of two elongated spots or short lines in the middle of the surface, a row of four small spots along the hinder margin, and usually six similar points on each side In general terms, we may say that the of the two middle ones. On the wingfalling-off is greater in those states which cases (elytra) we see ten black stripes, the beetle had fully occupied; but it is five on each namely, one close to the evident that other causes of fluctuation line of junction of the two wing-cases, must be at work to give rise to the varia- and one close to the outer margin, both tion in the amount of produce. Still, of which stop rather far from the apex of although the mischief done by the beetle the wing-case, and three between these, may have been exaggerated, it is certain, reaching nearly to the tip. The edges of from all accounts, that it is by no means all these black stripes are irregularly inconsiderable, and the recovery of the punctured, the punctures being partly on crops in some of the states which suffered the stripes and partly on the intervening most from the early visitation of the pale surface, and the second and third insect is directly ascribed by the govern-stripes from the suture are in contact ment statistician to the vigorous warfare which has been waged against it by the farmers. with each other at the base and apex. The legs have the knees and the feet (tarsi) black. Beneath the elytra the The beetle which has inflicted so much insect is furnished with ample membra damage, and caused so much alarm in nous wings, which it uses freely, and they the United States, that the prospect of are described by American entomologists its succeeding in crossing the Atlantic as of a fine rose-colour, and as giving has raised almost a panic in some Euro-the beetles a very beautiful appearance pean countries, is by no means a formi- when flying in the sun. dable animal to look upon. It is a beetle The species appears to be pretty gen of the tribe of Phytophaga, or plant-erally diffused in the Rocky Mountains, eaters, and of the family Chrysomelidæ, from the eastern slope of which it has all the members of which are of small invaded the cultivated regions by the or moderate size, of a rounded, ovate, or course already described. Although oblong convex form, with the head short found in the Colorado territory, it is by and deeply sunk in the next segment no means peculiar to that district, and (prothorax), the antennæ generally thread-the name of "Colorado potato-bug" like or beaded, and only of moderate commonly given to it does not indicate length, and the tarsi (feet) with only four the locality from which it set out on its apparent joints. The insect, as already eastward journey. Although several American entomologists of repute (such as Messrs. Walsh, Riley, and Shimer) have devoted considerable attention to the habits of the Colorado potato-beetle, its history, at least in one important point, has not been very satisfactorily worked out. There appear to be three generations of the beetles in the year. In the spring, when the potato-plants are quite young, the perfect insects produced from the last generation of the previous year lay their eggs upon the under surface of the leaves in small patches of from twenty to thirty together. The number of eggs produced by each female is said by some writers to be from 700 to 1,200, but this is probably an exaggeration. The eggs are of a yellowish colour. They hatch in about six days. The larvæ, which are at first of a reddish colour, grow rapidly, and become lighter in tint (of a more or less reddish cream-colour, or orange); they are full-grown in from seventeen to twenty days. In the mature state the larva is a thick fleshy grub, about half an inch long, having the head and the anterior segments narrow, the first three seg ments of the body furnished with jointed legs, and the extremity of the abdomen with a short process (anal proleg), which serves the animal as an additional limb in adhering to the plants on which it feeds. The head, the hinder margin of the first body-segment (prothorax), and the legs are black, and two rows of black spots are to be seen along each side of the body. face the forms of the various organs of the perfect beetle (head, legs, elytra, &c.), folded together and confined by a skin, which will be thrown off when it emerges as a beetle. The insects of the first and second broods of each year remain in this condition ten or twelve days, when they issue forth as perfect beetles, and the females quickly proceed to lay their eggs upon the potato-plants. How long the pupa of the third or last brood continue without further development does not appear to be very clearly known; but all recent observers agree that the perfect insects are produced before or during the winter, and that they remain underground until the spring. It seems to be certain that the beetles are found fully developed in the ground during the winter, although their descending to a depth of eight or ten feet, as stated by Mr. Riley, seems quite incredible, considering the form and structure of the insect. The same writer, however, says that they seldom go down below eighteen or twenty inches; probably they generally remain within the portion of ground which has been broken up in digging the pota toes, as this would furnish them with ample protection against the direct influ ence of cold, and the beetles would have no difficulty in making their way between. the clods to a suitable shelter. A curious quality has been ascribed to the Colorado potato-beetle, and, according to Mr. Riley, upon authentic evidence in some cases. They and their larvæ are said to possess poisonous properties which In many, if not in most of the insects have been known to affect people handbelonging to the family Chrysomelidæ, the ling them, and to produce serious illness anal proleg of the larva serves another pur- in those who have inhaled the vapours pose besides that of assisting its progres- given off during the operation of scaldsion; it produces a viscid secretion, by ing large quantities of the larvæ, or which the larva fixes its tail to the sur- burning potato-haulms infested by them. face of a leaf or other object before pass- Even the birds and domestic poultry ing into the quiescent pupa state. There were said at first to refuse to eat them; has been some discussion among Amer-and in one report we are told that the ican entomologists as to whether the prairie-hens alone would touch them, but western potato-beetle ever employs its that the flesh of the birds was rendered proleg in this manner, and the question so unwholesome by this diet that it could does not seem to be quite satisfactorily no longer be eaten with impunity. We settled; but Messrs. Riley and Shimer may suspect some exaggeration in these -the former of whom claims to be the statements, especially as we find at a first who ascertained the history of the later period of the visitation that sevinsect through all its changes-main-eral farmers found their fowls feed freely tain that it never undergoes its pupal upon the larvæ, and even recommended transformation attached to the plant the cooping of chickens in the potatoon which it has been feeding, but fields as a means of checking the pest. always descends to the earth, and un- Other birds also have probably accusder its protection sleeps out the pupa tomed themselves by this time to the stage. In this state the insect is a small taste of this novel food; at least, it has oval body, roughly showing at its sur-been observed in some parts of Iowa that 508 LIVING AGE. VOL. X. the rose-breasted grosbeak (Guiraca lu- to find that the most various methods doviciana) feeds freely upon the larvæ, some most absurd, others more or less and although this bird was formerly rather judicious of getting rid of the pest, rare, it has now become plentiful in the district. But if the birds have been inclined to fight shy of the western beetle, it has met with an abundance of insect foes in the course of its invasion. Among those which have rendered themselves prominent in this warfare, several species of lady-birds devour the eggs of the beetle; a tiger-beetle (Tetracha Virginica), and several Carabidæ, eat the larvæ ; a wasp (Polistes rubiginosus) carries them off to its nest to furnish provisions for its young; an Asilide fly (Promachus Bastardii) and several species of true bugs (Rhynchota), especially a Harpactor and an Arma, pierce the larvæ with their beaks and suck out the juices; whilst a Tachinide fly (Lydella Doryphora, Riley) attacks them by the insidious method of parasitism, depositing an egg upon the surface of the larvæ, generally near the head, and the young parasite produced from which burrows into the body of the victim and feeds upon its substance, not destroying it, however, until after it has descended to the ground when full grown. A long-legged spider or harvestman (Phalangium dorsatum) is also described as feeding upon the larvae in some districts; and the beetle has been found infested with adhering mites like those so constantly seen on our common dung-beetle (Geotrupes). should have been adopted. Of actual remedies that is to say, means of destroying the insect after it has taken possession of the potato-plants-the best seem to be the use of sweeping and beating nets, or substitutes for the latter, into which the insects are beiten by some implement, such as a flat broom, and the dusting of the plants with a poisonous powder composed of Paris or Scheele's green (arsenite of copper), mixed with from twelve to fifteen times its weight of flour or plaster of Paris. It is found that the use of this poison does not render the potatoes produced by the plants treated with it unfit for food, but it seems still to be doubtful whether the potatoes grown afterwards in soil upon which it has been employed are not injured in their quality, and Mr. Riley strongly recommends that it should be used as sparingly as possible. In his opinion, the most valuable remedial measures consist in the adoption of certain precautions in the selection of sorts for planting, and especially in the exercise of great vigilance in the spring of the year, placing in the newly planted fields small heaps of potatoes to which the beetles are attracted on emerging from the ground, and from which they may easily be gathered every morning, and destroying as many as possible of the eggs and young larvæ of the first brood. By these means it would appear that the increase of this new scourge of the potato may at least be considerably checked. From the published reports it would seem that these insect enemies of the potato-beetle being mostly natives of the soil, have exerted their powers of destruction so vigorously against the west- At the same time there is one circumern invaders as to have greatly checked stance in the history of the insect which their mutiplication, the numbers of the will probably stand in the way of its becarnivorous species having increased ing effectually controlled. In their progwith a rapidity proportionate to the ress through a civilized country the abundance of nourishment offered to beetles have cast off the simplicity of them. In the long run probably a bal- their western ancestors, and having once ance would be arrived at between the changed their food-plant, have now tried contending forces, but in the mean time many other articles of diet, and found the crops would be seriously affected, some of them highly congenial to their and the country would still always be taste. Besides various Solanaceæ growliable (like our hop-gardens) to the occa-ing wild, they have been observed feedsional excessive multiplication of the ing on species of Echinospermum, Amdestructive insects. Indeed with every ranthus, Helianthus, Cirsium, Sisym confidence in the ultimate establishment brium, Polygonum, Chenopodium, Eupaof a balance of power between the west-torium, and Hyoscyamus, and on grass, ern beetle and its enemies, the farmer oats, the red currant, and even the cabcould hardly be expected to look on with bige. This plasticity of appetite, if it equanimity while his potato-fields were may be so termed, acquired by an insect being ravaged; and it is not surprising which, in its original home, seems to |