How to Identify the Species of Brown & Black Spiders

Look at the body shape of the spider you're observing. Although all spiders have two main body parts, an abdomen and cephalothorax, and eight legs, the shape and proportions of these body parts can differ greatly from species to species. For example, flower crab spiders have extremely long, strong-looking front legs, compared to the rest of their bodies. Orb weaver spiders have rounded, bulbous abdomens that often seem slightly large in proportion to their heads and legs. Even within spider families, different spiders can have different shapes. Shamrock orb weavers are round, while golden orb weavers appear much more elongated.

Look at the head area, or cephalothorax, of the spider. You may need a magnifying glass to do this. Most spiders have eight eyes. Some, such as recluses, have six eyes. These eyes come in vastly different sizes in proportion to the head, and can be arranged on the head in different ways. Some spiders have eyes of two or three different sizes, such as those in the Lycosidae family. Some spider eyes ring the head, while others are arranged in straight lines, arches or form other patterns.

Observe the color of the spider. Both overall body color and markings or patterns, can help to identify a spider species. Brown and black spiders may be darker, more black in color or lean toward a more tan tone. These spiders might have subtle patterns on their abdomens, such as that of the wolf spider, or may even sport bright markings, such as the jumping spider has. Even within the specific species, coloration and patterns can vary. Use many different markers to help identify the exact species.

Look at the web of the spider. Many spiders can be identified by their webs. Funnel weavers, for example, get their name from the funnel-shaped web they build. Other spiders, such as the St. Andrew's cross spider, use specific patterns when spinning the web that are usually easily visible within it.