A.-Growth of the beet; weight of roots and leaves.

The result here given for June and August will justify comparison with the results obtained in this laboratory, where an equal increase of root to ten times its weight during three months of summer shows how necessary summer rains are to secure this growth in a given time.

The result of October 30 is not in accordance with that obtained here. At this period the tops in this latitude are not in that vigorous condition which the root is, and hence the ratio is vastly less than that given by Hoffmann. B.-Relative amount of water and dry matters.

The effect of season in augmenting the dry matters is evident in both tops and roots; remarkably so in the latter, so that by November 1 the dry matters had increased to 2 times the amount at 30th June, while that of the water present had diminished by one-seventh.

The increase of solid matter cannot be wholly set down to sugar, as Hoffmann's results would show; for our experiments prove that the percentage of sugar diminishes with the autumnal growth of the plant, while the gravity of the juice remains the same. The increase is chiefly cellulose, pecten and albuminous

The result of these tables is to show the increase of sugar up to November 1, a result wholly at variance with that derived from our experiments, in all of which varieties there was, as before stated, a remarkable diminution of sugar after the middle of September. If these discordant results on two continents are not due to differences in variety of plant as regards late maturity, or to climate, further experiments will be needed.

100 parts of ash (deduction made for carbonic acid and sand) yield:

It may be well to place by the side of these recent analyses the older one of the ashes of red beet, by Etti, and the English analyses of Way and Ogston:

The same analysts calculate that one ton of beets removes from the soil:

By comparing these figures with the analyses of the ash by Corenwinder given previously, it will be found that the ratio of potash to soda in the root is precisely the same in both specimens, although raised in different countries; also that the residues of the press are highly valuable for their alkaline constit

nents.

The result of all Mr. Hoffmann's experiments shows that the water in the leaves diminishes as they grow; the mineral elements also diminish. During the growth of the root the water also decreases. The cellulose and mineral matters do not increase except in the dry specimen.

With regard to the amount of azotized matter present nothing definite can be stated. The sugar gradually increases as the root develops; the pecten disappears and the sugar is produced at the expense of it.

Hoffmann's analyses of the second year's growth of the beets are not given here, as the saccharine relation terminates at the close of the first year. His results show that in the last year of the plant's life it gradually loses its sugar until it finally disappears a little before seeding.

I cannot conclude this account of the series of experiments carried out this year without acknowledging the valuable services of Dr. W. C. Tilden, assistant chemist, who has shown himself at all times zealous and capable in carrying out the details of the chemical examinations.

In order to make the laboratory a more efficient aid to the Department it is desirable that it should not be confined in its operations to the execution of analysis alone.

The relations of geology to agriculture, though not so close as those of chemistry, are yet sufficiently so to call for some attention to them, and to insure benefit to agriculture in its widest sense. Meteorology, chemistry, and geology are the three sciences which, next to botany, shed the greatest light on practical agriculture. Geology has been but lately cultivated in this direction, and in the hope of fostering the connection it is desirable that the Department should establish, in conjunction with the laboratory, a collection of geological specimens which would illustrate the agricultural and economic geology of the United States. Whatever relations of soils to their parent rocks exist would thus be brought out in a prominent and systematic manner, and as ample room can be afforded in the new building for the chemical division, it would be desirable to establish it on the removal from the Patent Office.

This subject, having already been brought under your notice, demands no further argument.

THOMAS ANTISELL, M. D., Chemist.

Hon. HORACE CAPRON, Commissioner.

REPORT OF THE ENTOMOLOGIST.

SIR: As full descriptions of the habits and natural history of the various insects injurious to our crops have been given in former reports, together with the most approved methods generally in use for their destruction, the present paper will be confined to those insects principally which have been the most numerous and injurious during the past year, or which hitherto have escaped

observation.

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The caterpillar, or cotton army worm, (Anomis xyline,) appeared last season in countless myriads, destroying millions of dollars' worth of cotton, and in many instances totally ruining the planters who relied upon cotton alone as their main crop. It is also to be feared, if effectual means are not soon devised for their extermination, that the planting of cotton must be abandoned for a time, at least in the most southern States, where these insects particularly abound, and most probably originate. As many planters have not seen our former reports on this subject, it may interest them to give a condensed description of the habits and transformations of this insect, so that they may be able to recognize it when it comes, and at the same time, perhaps, among themselves, devise some practical method of destroying it on its first appearance in the cotton field. In the more northern cotton States the cotton army worm is only an occasional visitor, ing rare as it approaches the north. In the extreme south they appear every season in greater or less numbers. As heavy frosts kill caterpillar, chrysalis, and perfect moth, its periodical appearance in certain districts is most probably owing to climatic influences, the insect being exterminated for the time whenever there has been extreme cold weather, and not appearing in that neighborhood again until replaced by fresh migrations of moths from more southern localities, where the frost had not reached. An old cotton planter in South Carolina states that the moth made its appearance periodically every 21 years in his district, hav ing been very destructive in the years 1804, 1825, and 1846. "Moreover, it had actually been foretold that in the year 1867 the caterpillars might be expected to destroy the crops." This was certainly a very strange coincidence, but proves nothing, as, unlike the 17 years' locust, whose whole 17 years of disappearance is said to be spent under ground, and whose habits and natural history we are therefore unable to trace, I have bred the cotton fly or moth from the egg up to the perfect insect, and the whole of its transformations do not occupy a period of

more than a few weeks in the summer or autumn.

As false alarms about the appearance of the cotton worm in certain districts are frequently inserted in the southern newspapers by persons interested in the sale of cotton when the worms seen in the field are merely boll worms, grass worms, or some other comparatively harmless caterpillar, I will mention some distinguishing marks by which the cotton moth may be recog nized in either the egg, caterpillar, chrysalis, or perfect state. In the first place, the egg of the cotton worm is round and very much flattened in form, and of a green color, whereas the egg of the boll worm moth is round, somewhat bluntish, conical in shape, and of a yellow color. The egg of the cotton worm is mostly deposited on the leaf or branches, while the egg of the boll worm is usually placed in the so-called "ruffle" or envelope of the flower.

The caterpillar of the cotton worm has six pectoral or front feet, two anal, and eight ventral, the two foremost of the ventral feet being very small, apparently useless, and not employed for grasping, like the other six; while in the grass worm the legs are all perfectly formed and used when creeping from leaf to leaf. Owing to this imperfection in the formation in the first pair of ventral feet, the cotton caterpillar always moves like the span worm or looper, that is, by alternately contracting and expanding its body, holding fast by means of its hind feet to the object on which it rests, while the head and fore feet are extended as far as possible, the stalk or leaf being securely grasped by the pectoral feet, the hinder part and legs are suddenly brought up to them, so that at every step the body assumes the shape of an arch; whereas the grass worm glides along by moving its feet alternately and gradually without raising the middle of its body from the leaf. The cotton worm has also a habit of doubling itself up suddenly when disturbed, and springing to a distance, but the grass worm merely rolls itself up somewhat like a snake when coiled. The cotton worm, when about to change, spins a very loose web or cocoon among or in the leaves or branches of the cotton plant or weeds infesting the field, at some distance from the ground. The grass worm, on the contrary, comes down from the plant it has fed on and retires under stones, loose earth, or buries itself in the ground before forming its cocoon. The perfect moth of the real cotton worm is much more angular and graceful in form, with the upper wings of a somewhat reddish or claret colored brown, and there is always a darker spot having a light centre, more or less defined in the middle of these wings, while the under wings are of a dark aṣh color. The grass worm moth is much more clumsy in form, its upper wings being clouded and barred with dark and light grayish brown, while the under wings are lighter colored.

Whether the cotton caterpillar feeds upon any other plants or not I am unable to say, never having found it eating anything but cotton, and even when seen on weeds in cotton fields the worm has merely wandered away to find some suitable locality in which to spin its cocoon. Several cotton worms, kept for the purpose of experiment, constantly refused to eat anything but cotton, although supplied daily with fresh leaves of all the weeds or plants in the neighborhood, and several actually starved to death rather than touch anything but cotton as a food.

The caterpillars appear more or less, almost every season, in some of the more southern Florida plantations, sometimes in a very sudden and unaccountable manner. Mr. E. Richards, of Cedar Keys, wrote a very interesting letter some years ago to the Department, which appeared to prove that the moth is exceedingly migratory in its habits and capable of flying great distances; as in many places where they have suddenly appeared in great numbers there has been no method of accounting for their presence excepting that the worms had previously subsisted on some other wild plant or weed, and left their original food for the cotton, which was more nutritious or congenial to their taste, or that the moth had migrated from a great distance. Mr. Richards, in his letter, says:

The last of July, 1845, these caterpillars made their appearance in a small field of three or four acres of sea-island cotton planted on Way Key, an experiment to see if cotton could not be advantageously cultivated on the keys, no other cotton having been previously planted within 80 miles of them, but the whole crop was destroyed. The caterpillars at the same time were destroying the cotton in the interior of the country.

As far as the habits of the cotton caterpillars are known, whenever they have appeared in Georgia or South Carolina they almost invariably came from