Shoemaker's pamphlet "Felis Catus in Pennsylvania" describes an incident on January 16, 1922 in which a wildcat was killed in Nockamixon (Bucks County) by 16 year old Tunis Brady. Frightful screams had been heard in the vicinity for three years. A detailed description of the dead animal quoted in the pamphlet describes a cat about 2 1/2 feet in length and a foot in height, with a broad head. It was a smoky gray color, with yellowish patches on its undersides. It had an 11 inch long tail which was bushy and rather like a raccoon's. It had a white spot on its throat and was marked with black stripes. At the time, it was believed that the animal may have been similar to a European wildcat (Felis sylvestris) and the original article describing Brady's kill is quite clear on its not being a bobcat (Lynx rufus) or lynx (Lynx lynx).
Elsewhere in Shoemaker's article it is described how just such an animal was kept in the Philadelphia zoo, and labelled an "Indian Devil". Similar animals were to be found in the Blue Ridge Mountains and also in the Chestnut Ridge area in the western part of the state. In around 1920, Daniel Trouts killed two similar wildcats in the same area as Brady's kill. Robert Lyman's Forbidden Land describes these wildcats as being recorded from Potter County.
Karl Shuker has noted that long-tailed specimens of the normally short-tailed bobcat and lynx have been recorded. In fact, despite the early denials, the size of the animal and coloration meshes perfectly with commonly-accepted traits of the bobcat. The striped markings of the animal may not line up perfectly, but as some lynx subspecies such as the Iberian lynx have coats with a striped appearance, this is not out of the ordinary either.
Furthermore, bobcats can be melanistic (black). I have been wondering whether a melanistic long-tailed bobcat could account for some of the sightings of "black panthers" often recorded. Also, a wildcat with similar markings to the Nockamixon one could account for sightings of "tigers".