Want this question answered?
It is the common "Daring jumping spider," Phidippus audax. It's completely harmless.
is it a tarantula? if so, it's a Mexican redknee tarantula. http://www.Google.com/search?hl=en&q=Mexican+red+knee+tarantula&btnG=Google+Search
There are a number of different spiders that could be described as black spiders with a red dot on their back including the Black Widow, the Australian Redback spider and the Jumping Spider.
The male green jumping spider has a dark red head and a bright green body. The scientific name for this spider is Mopsus Mormon.
A black spider with a red back and thick fuzzy legs is commonly called a jumping spider. The formal name is Phiddipus audax.
It can be hard to tell what kind of a spider you are looking at that has a red head and back and black and white striped legs, since the body type is also an important factor. Chances are that it is a red-headed jumping spider, which can cause a somewhat painful bite but is not otherwise dangerous to humans.
red back spider
Some species of black widow have a red dot. A redback spider, the equivalent of a black widow in Australia, also has a red dot on its back. It is all black and quite small and has a big red patch on its back. it is highly venomous. See the related link below for a picture.
It could be a black widow spider if it is small and thin-legged with a shiny round black abdomen and red markings under it. If it's fuzzy with a red spot on it's back, and the front part of the body is more-or-less the same size as back part, then it's a black jumping spider.
A green spider with a red spot is dangerous if it is a red back. Normally, green spiders are not dangerous.
A RED BACK!!! bY THE WAY I WOULDN'T TOUCH IT!! THEY ARE REALLY DEADLY, ESPECIALLY THE BABY ONES!!! ^ i wouldn't pay attention to that If the red is on the belly then worry more, it the red is on the back its not a black widow, ive seen a bunch of spiders with a black body and white stripe, they are jumping spiders, the red button i don't know much about.
A red and blue spider is called the Red-Headed Mouse Spider and the scientific name is Missulena Occatoria. These spiders are considered dangerous because they are known to produce high amounts of toxic venom.