#10: Red-Spotted Orb Weaver
Araneus cingulatus, or the red-spotted orb weaver, belongs to the orb-weaver family Araneidae. You can find this spider in Pennsylvania as well as throughout parts of the central and eastern United States. Adult red-spotted orb weavers measure between 3 and 5 millimeters long, with females measuring larger than males. Their species name, cingulatus, comes from the Latin cingulum or “belt.” The top of the abdomen looks primarily cream-white, except for a row of red spots that run along the outside of the abdomen. That said, these spiders have an abdomen that can sometimes look pale green and feature white or reddish splotches. Meanwhile, the cephalothorax and legs look bright green. Red-spotted orb weavers make wheel-shaped webs that they use to capture their prey. Due to their small size, their bite is not dangerous to humans, as their fangs normally aren’t large enough to pierce human skin.
#9: Wetland Giant Wolf Spider
The wetland giant wolf spider, Tigrosa helluo, is one of several wolf spiders in Pennsylvania. It belongs to the family Lycosidae and ranges throughout the eastern half of the United States. You can typically find it in forests, fields, and marshes with access to plenty of freshwater, hence its name. On average, adult wetland giant wolf spiders measure about 17 millimeters long. That said, females tend to measure larger than males. The carapace and abdomen look primarily brown. However, these spiders feature a characteristic yellow stripe down the middle of the cephalothorax and dark spots under the abdomen. Wetland giant wolf spiders actively hunt instead of using webs to catch their prey. They spend most of their lives alone, and so most of them learn to rely on their excellent eyesight and reflexes to survive. Their bite is not medically significant, and they rarely attack humans.
#8: White-Banded Fishing Spider
Dolomedes albineus is also known as the white-banded fishing spider. It is a member of the nursery web spider family Pisauridae. If you want to find this spider in Pennsylvania, your best bet would be to look near streams, ponds, or other bodies of water. Adult female white-banded fishing spiders can grow up to 23 millimeters long, while males can reach lengths of up to 18 millimeters. Their primary color varies depending on the specimen, but most white-banded fishing spiders tend to look brown or mossy green with dark markings. These spiders feature a white band in the space below their eyes, around the jaws, and occasionally around the entire carapace, hence their name. White-banded fishing spiders actively hunt for insects and small fish using their legs as fishing lures. They can also run across the surface of the water or dive into the water to catch food. Their bite is not medically significant.
#7: Northern Black Widow
The northern black widow, Latrodectus variolus, is one of the most poisonous spiders in Pennsylvania. It belongs to the cobweb spider family Theridiidae and ranges throughout the eastern and northern United States and southern Canada. Adult female northern black widows measure between 9 and 11 millimeters long, while males measure 4 to 5 millimeters long. They appear primarily black except for a red hourglass-shaped marking on the top of the abdomen. However, unlike other black widows, the red hourglass is rarely intact and typically appears broken. Northern black widows build messy, irregular cobwebs that they use to capture their prey. While they rarely bite, their venom contains a potent neurotoxin that can cause latrodectism. Common symptoms include pain, sweating, vomiting, and muscle rigidity. Although bites rarely prove fatal, very young or immunocompromised individuals are susceptible to serious medical complications.
#6: Magnolia Green Jumper
Lyssomanes viridis, or the magnolia green jumper, belongs to the jumping spider family, Salticidae. Given that its genus, Lyssomanes, was one of the first genera of jumping spiders to evolve, researchers pay particular interest to this tiny spider. You can find it throughout the southern and eastern United States. Adult female magnolia green jumpers measure around 7 to 8 millimeters long, while males measure from 5 to 6 millimeters long. They are one of the most visually striking jumping spiders in Pennsylvania due to their pale or translucent green color. Their abdomen also often features small scales in a range of colors, from red to orange to yellow to white. Magnolia green jumpers can leap around 3 to 4 times their body length, which is slightly shorter than most other jumping spiders. That said, they possess relatively longer legs than other jumping spiders, which may make them better at chasing down prey.
#5: American Green Crab Spider
The American green crab spider, Misumessus oblongus, belongs to the crab spider family Thomisidae. It is the only member of its genus, Misumessus. You can find this tiny green spider in Pennsylvania and throughout the eastern United States. Adult American green crab spiders measure from 3 to 7 millimeters long, with males typically measuring smaller than females. Their legs, abdomen, and cephalothorax appear primarily pale or translucent green. That said, these spiders feature a thin red line around the front half of the distinctively diamond-shaped abdomen. Like other crab spiders, they can walk forward, sideways, or backward like a crab. Instead of using webs, American green crab spiders wander around in search of prey. They typically wait on flowers and snag insects that come to feed on the pollen or nectar using their long legs. Due to their small size, they pose no danger to humans.
#4. Broad-Faced Sac Spider
Trachelas tranquillus is more commonly known as the broad-faced sac spider. A member of the ground sac spider family Trachelidae, it is widely distributed throughout the central and eastern United States and Canada. You can find this spider in Pennsylvania under stones, boards, or leaf litter or crawling on window sills and siding. Female broad-faced sac spiders measure from 7 to 10 millimeters long, while males measure between 5 and 6 millimeters long. Their carapace and mouthparts, or chelicerae, appear reddish-brown. Meanwhile, these spiders have an abdomen that can range in color from light grey to yellow. During the day, broad-faced sac spiders hide in silken retreats and then emerge at night to find food. Unlike most other spiders, broad-faced sac spiders willingly scavenge and eat dead insects and other spiders. While rare, their bite can cause severe secondary infection in addition to significant pain. However, most bites do not require medical attention.
#3. Bridge Orb Weaver
The bridge orb weaver, Larinioides sclopetarius, is the second orb-weaver to make our list of spiders in Pennsylvania. In addition to the United States, you can also find it in Europe, Mexico, Canada, and parts of east and central Asia. Female bridge orb weavers measure between 10 and 14 millimeters long. Meanwhile, males typically measure 8 to 9 millimeters long. They look primarily grey and sport tan and white bands on their legs. The top of their abdomen features a light grey marking in the shape of a cross, which leads some people to call them grey cross spiders. Bridge orb weavers often build their webs on manmade structures such as bridges, hence their name. Their webs can measure nearly two feet wide and normally rest in places that get plenty of sunlight. They rarely bite humans, and even when they do, their bite is not medically significant.
#2: Common House Spider
Parasteatoda tepidariorum is more widely known as the common house spider. It easily ranks as one of the most common and frequently-sighted spiders in Pennsylvania. A member of the family Theridiidae, you can often find it in or near human dwellings, hence its name. Female common house spiders generally measure between 5 and 6 millimeters long. Meanwhile, males typically measure from 4 to 5 millimeters long. They come in a range of colors from black to tan and feature a variety of markings on the abdomen. People sometimes mistake them for black widow spiders due to their similar size, shape, and color. Due to this confusion, people refer to species in its genus, Parasteatoda, as false widow spiders. Common house spiders make irregularly-shaped cobwebs that they use to capture prey. Their poisonous bite may harm insects but poses no danger to humans.
#1. American Nursery Web Spider
The American nursery web spider, Pisaurina mira, is the second arachnid in the family Pisauridae to make our list of spiders in Pennsylvania. As its name implies, you can find it primarily in the United States, although it ranges throughout eastern North America. Adult female American nursery web spiders can reach up to 19 millimeters long, while males measure noticeably shorter. People often mistake them for wolf spiders due to their similar appearance. They usually appear brown or tan, with an abdomen nearly twice as long as the carapace. Although their abdominal markings can vary, these spiders typically possess either a dark median band or a light band with two rows of spots. American nursery web spiders actively hunt for prey instead of using webs. That said, they do make webs to hold their eggs, hence their name. Since females often cannibalize males, males frequently bind the females’ legs while mating to avoid being eaten.
