We are continually hearing from abroad of gifts of land for parks, by liberal individuals, as perpetual places of enjoyment for pent-up citizens. A Mr. Adderley has just given ten acres forever to the working people of Birmingham; and yet our Philadelphia Legislators have possessed, for twenty years, One of the finest sites for a park, and, instead of improving it, have actually allowed a miserable tenant to despoil it annually of its trees and rocks, and disfigure it in every way. This is one of the most extraordinary instances of imperfect legislation on record. A few gentlemen have had influence enough to get Hunting Park Course improved, and an enthusiastic writer, who well deserves to be heard, has issued at his own expense a pamphlet, deprecating the neglect of Pratt's Garden, without effect. Citizens of Philadelphia! rise up in your might, and displace from office every man who acts so contrarily to the dictates of humanity and civilization!

Since the above was written, the City Councils, on the motion of that excellent member, Theodore Cuyler, Esq., have taken measures to displace the present tenant at Lemon Hill, and probably something may yet be done. We ask of members of the Councils a little consideration on the subject. Those who vote against improvement may depend upon the frowns of their fellow-citizens.

The Park #1

There is scarcely a subject connected with the topics appropriate to this Journal that interests the lover of trees, scenery, and humanity more intensely than that of Parks for the people. It has been long a topic of the Horticulturist, which indeed has the credit with many of having originated and encouraged the idea for New York and other places. When once a good specimen is seen, our people will excel in the formation of pleasure grounds, and we shall have them attached to every city and town where there is a particle of taste or public spirit. One good example will prove sufficient to stimulate our population everywhere. It is consequently of the greatest interest that the park, commenced with so liberal a capital, should be correctly and artistically planned and finished. Various correspondents have sent us their ideas, and others have overwhelmed our tables with newspapers and so forth, as if expecting the Horticulturist would take sides with this or that party struggling for power. This we cannot do, nor can we ever be content to give a partisan coloring to these pages.

But there is a right and a wrong way of making parks, and we look on for the present with intense interest on what is going forward, quite incompetent to contend with the politics and the politicians, who have torn the whole subject into shreds, and shall we say "patches." When the fog has cleared up, we mean to look after the Park, and meantime select the following communication from the many appeals before us, as the most suitable one we have received to place before our readers. Mr. Chorlton when he takes his pen is very apt to know what he is about. Some of the best qualified to advise respecting the Park have stood in the back ground, because park-making is like painting a fine picture, and they ask if Wouvermans or Claude Lorraine would consent to produce a master-piece under orders of a political mayor, or have their little bill of road-making disputed by the common council, who would call a willow an oak, and wonder what people wanted better than any shade tree that would cost the least money.

But after all, we are to have a Park.

Some fear is expressed as to the safety of entering or crossing it at night, when there will be so many places of concealment for rogues and murderers.

Parks #2

On the 15th instant, the plans for a park at Fair Mount, Philadelphia, are to be examined and decided on: we learn that there will be considerable competition. As to situation and water frontage, Philadelphia has the advantage, but in size and magnificence, the example is that of New York. The Central Park is being pushed through by Mr. Olmsted, the superintendent, as fast as large means will allow. He appears to be most energetic, and is determined to accomplish all that lies in his power while the opportunity is presented. In January we saw 2,200 men employed, and were glad to observe that Mr. Calvert Vaux had been appointed assistant architect to the great work.

The Parks #3

In my investigations of this subject, I have visited most of the Parks of New York, and many of the streets of this city. The Central Park is, like your Greenwood, clear of the span worms. There the birds are protected, with no hawks to kill them, nor crows or squirrels to rob their nests, and they are found in such numbers as to keep all such insects in check.

Of the other Parks, the Washington Parade Ground has the fewest; the keeper here told me that they were nearly gone, and the foliage of the trees showed but little injury. Two years ago this square was as much infested as any other part of New York. The trees on the Battery and in the Park, as well as those in front of the Hospital and about Trinity Church, have all suffered, but all are still shade trees, and not as they have been some years, almost as bare as in winter.

Union Square has suffered most, though some of the trees in Madison Square bear the signs of having fed their full share of the worms. The rows of small sized trees in the streets seem to suffer more than the same kinds in the Parks; there the birds are seldom seen, and probably the parasite flies prefer more protection.

The keeper of the Park on Union Square informed me, that two years ago a flock of four or five hundred Cedar Birds (the Wax Wing) were feeding on the worms for several days in that Park, and he supposes that if they had not been frightened away, they would have taken them all; and when told that the worms in that Square were thicker than in any other in New York, he seemed much sur-* prised. The Cedar Bird feeds chiefly on berries, and these were probably on a marauding expedition to some of the city gardens in pursuit of early cherries, and merely came among the worms between meals, by way of variety. It is a habit of this bird to be very circumspect when stealing cherries, and to stay about the trees no longer than is necessary. All the testimony I could get from policemen and others both in New York and Brooklyn, seemed to concur with my own observations, that the worms were not more than half as numerous this year as last, and that two years ago - 1860 - they were the most numerous.

As nothing has been done to destroy them, it becomes an interesting inquiry, as to the cause of this diminution.

The rate of increase in insect life is generally enormous, and this one is not an exception to the rule. The number of eggs in the clusters left by the millers of the span worm, varies from eighty to two hundred and thirty. In examinations of the eggs deposited last year, every one has a little opening in the end, where the young worm seems to have safely escaped. You have but few of the little creeper birds in your Parks, and found chiefly in winter, that with their sharp beaks peck into and feed upon the eggs of insects. You have never yet had the worms in such numbers as to destroy the foliage of your trees before they arrived at maturity, and thus, from starvation, come to an untimely end, as insects sometimes do.

In theorizing on this matter, I supposed this decrease of numbers was brought about by that class of insects that has in charge the regulating of the insect world; and since your invitation, I have taken some pains to ascertain whether the facts will sustain that theory, and have found enough to prove that they do.

As a matter of science these investigations have been to me profoundly interesting. To you, who are so anxious to get rid of this worm pest, it will be welcome news to know that they are likely to aid you greatly in your labors.

As but little is generally known of this Ichneumon or Parasite class of insects, to which we are so much indebted for its controlling power over other classes, it will be well to give a brief explanation before going further.

There is nothing in the other departments of nature exactly corresponding to this class of insects. In the vegetable world, the Mistletoe is a fair illustration of the parasite, but it does not kill the tree upon which it feeds.