Other Common Names
official list (PDF doc) of common names by the American Arachnological Society
Synonyms and other taxonomic changes
referred to as Araneida by some sources
all North American spiders belong to suborder Opisthothelae
Identification
Two body parts:
cephalothorax and
abdomen
Eight
legs attached to cephalothorax
Anatomy:
See images:
Sex Identification:
Look at the front of your specimen, where the "face" of the spider is. You will find two small appendages that resemble little legs. These appendages are called
pedipalps, and are used for sensing the spider's immediate environment, for assisting with eating, and for males, reproduction (specifically sperm deposition). Please refer to the Anatomy section above for a picture of a spider with the pedipalps labeled.
If the pedipalps resemble boxing gloves (the tips of the pedipalps are swollen), it is an adult male. Here is an example of an adult male (Agelenopsis grass spider):
If the pedipalps are not swollen, it is either a female, or an immature of either sex. (Characteristics of the female genital opening, the
epigynum, may be used for species-level identification.) At this point, more information is needed about the spider (shape, size, location, coloration, style of web, etc.); this information can be used to determine the maturity level of the spider, which would indicate whether it is an adult female or an immature spider of either sex. Here is an example of an adult female (ground spider):
Life Cycle
Spiders must molt to grow. Check out Jeff's amazing series of images:
Remarks
Believe it or not, almost all species are not harmful to people, but are actually beneficial because they catch and eat a lot of insects that can be pests. Spiders do not seek out, chase, or randomly attack people, nor do they carry grudges against people. If you leave them alone, they will leave you alone.
Most people are bitten because they were playing with the spider (which is effectively "asking" to be bitten), or the spider felt threatened without a chance to escape; many times, surprising the spider was completely accidental. Depending on your geographical location, there are only a few spiders that you need to be familiar/concerned with (see the comments below on the spiders of potential medical concern).
If you aren't sure whether the spider you have might be harmful, leave it alone and do not kill it. If you have to move it, please refer to the "Relocating The Spider" comments below.
Spiders of Potential Medical Concern:
Brown Recluse:
Guide Page
Yellow Sac Spider:
Guide Page (both
C. mildei and
C. inclusum)
Moving most spiders to a new location (outside the house?) is not difficult. You will need the following:
- a clear glass or cup; it should be clear so you can see where the spider is.
- a card, or stiff piece of paper
(1) Carefully place the cup over the spider (careful not to pin the legs under the rim of the cup).
(2) Gently and slowly slide the paper under the glass; as you push the paper under the glass, let the spider walk up onto the paper.
(3) Once the paper is completely underneath the cup, gently pick up the paper and glass, making sure not to create gaps between the paper and glass (the spider might escape, which means you have to start all over again... :) ).
(4) Turn the glass over while keeping the glass covered with the paper.
(5) Take the spider to the new location, while holding the paper over the glass.
(5a) This is a good time to look at your spider, examine its markings, and learn about it.
(6) Place the glass on its side on the ground and remove the paper.
The spider will walk out of the glass in a few moments. If it seems reluctant to exit the glass, gently tilt the opening the glass toward the ground, and gently shake. The spider will eventually wander out. :)
Print References
Levi
(2) - Very good, inexpensive guide about commonly found spiders and other arachnids.
Internet References
Note:
When looking up spider images and info on the internet, make sure it is for "your" geographical area. There are many sites from other countries, such as Australia, that have some very nasty spiders, but they are not of concern in North America. (Example: There is an Australian funnel-web spider (very big and very nasty), which IS NOT related to the Agelenid funnel-webs (common to the US and Canada), but if you look up funnel-web spider, guaranteed you'll find links to the Australian funnel-web!)
Information:
Ohio State University Extension Fact Sheet: An excellent article about spiders in and around the house.
Texas Agricultural Extention Service: A good discussion about spiders in Texas
Spiders of Canada: An excellent article about spiders families in Canada.
Anatomy:
The Anatomy of a Spider: A well done, detailed (but simple to understand) discussion of spider anatomy.
Spiders of Medical Concern:
Potentially Medically Significant Spiders of North America: A good, thorough article about spiders that have a bite that requires medical assistance.
Myths and Truths about Spiders:
Common Myths about Spiders: A very good FAQ about many of the misconceptions and truths about spiders.
Eye Arrangements of Some Eight-eyed Spiders:
Common Myths about Spiders: A front view of carapace of 5 genera and 5 families of North American spiders, showing eyes.
Eye Arrangements of Some Spiders on BugGuide:
Visually Identifiable Spiders:
