Extracts of Three Letters, One, Concerning Some Philosophical Inquiries about Spiders, together with a Table of 33 Sorts of Spiders to be Found in England; as Also of a Kind of Viviparous Fly: The Second, about an Insect Feeding upon Henbain, and Thereby Qualifying in Its Body the Horrid Smell of That Plant, and Altering It to an Aromatical and Agreeable One: The Third, Containing Some Observations of Glow-Worms