Another Letter, Written of the Same Gentleman, from York Sept. 13, 1671. Enlarging His Former Communications in Numb. 75 about Vegetable Excrescencies, and Ichneumon-Worms

if there shall not be enough specifically to distinguish them, and hinder them from being sampled by any thing of the spoils of the Sea or fresh waters or the land-snails; my argument will fail, and I shall be happily convinced of an Error. Another Letter, written of the same Gentleman, from York Sept. 13. 1671. enlarging his former Communications in Numb. 75. about Vegetable Excrescencies, and Ichneumon-Worms. SIR, In my last Paper about Vegetable Excrescencies, I was wholly silent of the opinion, which Mr. Willoughby is pleased to favour; and because that worthy Gentleman hath so far made it probable, that now it seems only to depend upon the good fortune of some lucky Observer, I am willing to reassume my former thoughts, that all those odd Observations, we have made of the Births of Ichneumon, do but beget in me a strong belief, that they have a way yet unheeded, whereby they do as boldly, as subtly, convey their Eggs within the Bodies of Insects and parts of Vegetables. A fifth and last proposition of that Paper * was, that the substance of many Vegetable Excrescencies seemed not to be the food of the worms to be found in them. My meaning was, that the substance of the Vegetable Excrescencies in which those Ichneumon worms were to be found, was rather augmented, than diminished or worm-eaten. And the like conformity of their feeding within Insects is well observed by Mr. Willoughby *, that the impregnated Caterpillars seem not to be concerned, though their bodies are full of Insects of a quite different kind, but go on as far as they may towards the achievement of the perfection of their own species. Thus I have seen a Poppy-head swollen to a monstrous bulk, and yet all the Cells were not receptacles of Ichneumons, but some had good and ripe seed in them. I shall not refuse Mr. Willoughby (though you know upon what grounds grounds, I have twice done it to you) the satisfaction of an Answer to my roth Quare, by him resolved negatively: It is true, the swarms of the Ichneumons, coming out of the sides of Caterpillars, do immediately make themselves up into bunches, and each particular Theca, from the Cabbage-Caterpillar (for example,) is wrought about with yellow silk, as those from the black and yellow-Jacobea-Caterpillar with white, but as for web to cover those bunches of Theca's, I never observed it but in the green Caterpillar so common in our Lincolnshire-heaths, which are affixed to Bents or other plants. These in truth never deceived but my expectation, for I verily thought I had found, when I first observed them, a Caterpillar equivalent to the Indian silk-worm; but having cut them in two, and expected to have found a Caterpillar's Chrysalis in the middle, there presented themselves a swarm of Ichneumons. These are as large many of them as my thumb, that is, at least four times bigger than the Folliculus or Egg-bag of any English spider that I ever saw yet. By good fortune I have not thrown away the boxes, wherein I made the Observation concerning Ichneumons feeding upon the Eggs of certain Spiders; I have had them in several boxes, some 8, some 10, some 12 days in Vermiculo, feeding upon the very cakes of Spiders' eggs, before they wrought themselves Theca's for further change; and they seldom exceeded the number of 5 to one cake of Eggs, &c. so that you may assure Mr. Willoughby, this is no conjecture, but a real observation accompanied with more circumstances, than I am willing at present to relate. An Accompt