Brown recluse spiders are most easily identified by the presence of a violin-shaped mark on the top of the cephalothorax. The neck of the violin points toward the rounded abdomen of the brown recluse spider. Another telltale sign of a brown recluse spider is the presence of six eyes arranged in three pairs. However, the violin marking is less distinct in young insects and the eyes of a brown recluse are only visible with the help of a microscope. Further distinguishing characteristics may be necessary for proper identification.