Calymene blumenbachii; Print; Calymene blumenbachii; sometimes erroneously spelled blumenbachi; is a species of trilobite discovered in the limestone quarries of Wren's Nest Hill in Dudley; England. Nicknamed the Dudley Bug or Dudley Locust by 18th century quarrymen it became a symbol of the town and featured on the Dudley County Borough Council coat-of-arms. Calymene blumenbachii is commonly found in Silurian rocks (422.5-427.5 million years ago) and is thought to have lived in the shallow waters of the Silurian; in low energy reefs. This particular species of Calymene (a fairly common genus in the Ordovician-Silurian) is unique to the Wenlock series in England; and comes from the Wenlock Limestone in Much Wenlock and Wren's Nest in Dudley. These sites seem to yield trilobites more readily than any other areas on the Wenlock Edge; and the rock here is dark grey as opposed to yellowish or whitish as it appears on other parts of the Edge; just a few miles away; in Church Stretton and elsewhere. This suggests local changes in the environment in which the rock was deposited.