North America has approximately 3,000 species of spiders , but most of these do not pose a terror to humans . In fact , since they are predators , they do the avid gardener a great service when they shoot down dirt ball pestis . spider have eight legs , unremarkably four brace of eyes , an belly and a cephalothorax . If you want to key out the spiders in and around your habitation , the most distinguishing features are color and size . Several spider , with black torso and light and dark dark-brown legs , exist in North America .
Step 1
At least two spiders live that are nick - named " ant mimic spiders " with black bodies and brown leg . The Coleosoma acutiventer species has a shiny black body with reddish to light and dark brown striated leg . With a body length of around 1/5 column inch , they look like ant because their abdomen are stretch and purloin to make them look like worm with three body segment . Slightly bigger than the Coleosoma species , Falconina gracilis is another wanderer species that looks similar to an ant . These spiders have a colored brown stomach with an ellipse shape and a glazed bleak cephalothorax . They have amber to light brown legs segmented with disconsolate coloring material stripes .
False Black Widow Spider
The false black widow spider ( Steatoda grossa ) has this mutual name because it looks like the venomous black widow woman spider . Both species have bulbous abdomens and black trunk , and build similar webs . But unlike the transparent dark consistency and ruby-red hourglass marking of the true widow spider , the abdomens of false widows are marked with picket to golden markings amidst a shameful backdrop . imitation widows have blue leg with lighter brownish mark . They stray in size of it from 0.2 to 0.8 inch .
Step 2
Red Widow Spider
Like the fatal widow , the red widow spider ( Latrodectus bishopi ) is venomous to human race . If you think you have been bitten by one , immediately essay aesculapian status . Generally , red widows tend to be shy and will not bite unless they are disturb . Where black widow spiders are totally black with a red hourglass strike out on their bottom , crimson widow woman have reddish - brown legs and cephalathorax and a burnished black abdomen . Often the sinister abdomens are marked with a quarrel of ruby spots . grownup ruby-red spider may measure 1 1/2 inch when their legs are offer .
Ground Spider
Ground spiders ( Nodocion spp . ) image in size from 0.08 to 0.7 inches . Their cephalothorax and venter are benighted brown to smuggled and shiny . Their abdomens are particularly distinctive with an elongated and flattened shape . priming spider legs are reddish brown with darker chocolate-brown segment .
