This section is from the book "The Gardener's Monthly And Horticulturist V26", by Thomas Meehan. See also: Four-Season Harvest: Organic Vegetables from Your Home Garden All Year Long.
Mr. Shriver, of Wytheville, Virginia, sends us some very pretty galls from a rose bush. They are about the size of small marbles, thickly studded with slender spines like rose thorns. We sent the letter to Mr. Homer Bassett, of Waterbury, Conn., who is one of our leading students in this class of insect work. Mr. Shriver's letter has not been returned, but the remarks of Mr. Bassett will be readily understood without.
"The gall sent by you is that of Rhodites bicolor, Harris. Described by Dr. Harris (Inj. Insects, pp. 548-549), as Cynips bicolor. Baron Osten Sacken gave a very full description of the same in the first or second volume of the Proc. Ent. Soc. of Philadelphia. I am not certain as to the volume, as I am away from my library.
"Mr. Shriver's questions are not easily answered.. In regard to the first, Why is the hollow in the gall so large? I may say that a large number of galls furnish their occupants as much, and some of them vastly more room - but this does not answer his question. As answering it in part, I may add that as a rule galls reach their full development long before the larva is full grown, and in many cases before the larva becomes large enough to be seen by the naked eye. This fact, if true of all species (it may not be), is against the theory that the growth of galls depends upon the irritation caused by the larva while feeding upon their inner walls.
"Why, Mr. Shriver asks, does this particular species take its spiny character? He quotes Dr. Haller's assertion that the origin of the gall is the germ of the flower. If Dr. Haller refers to this species, or even to species in general, I must differ with him. I am not sure that this species of gall is developed from ordinary leaf buds, but think this is the case. I know that the woolly oak-galls, C. q. operator and C. q. summator (I cannot recall the generic names of those species, lately given by Dr. Mays) are both developed from leaf buds - one species affecting the petiole of the embryo leaf, and the other the base of the leaf - and that the woolly covering is nothing but a monstrous development of the pubesceum of the leaf.
"Strange as are the forms of galls, there, is in most cases, some attempt on the part of the plant to put on some of the characters of its normal growth.
"Of course Mr. Shriver is aware that from the grubs found in galls, gall-flies are produced. These are of many species, and the common wild rose has several kinds of galls, each kind producing a distinct species of gall-fly.
"If Mr. S. should find that the galls of Rhodites bicolor produce (as they often will) different sorts of insects, he may be sure that only one of them is the producer of the gall - the others are parasitic.
"I cannot now command the time necessary to give a full reply to the questions asked by Mr.
Shriver or to write out the interesting facts they all to mind".