I can't get a good enough look at the to tell anything about their body. Try putting one or more on a white piece of paper and do the best close up you can.

I looked around and this is the next best answer I came up with:-

These are actually little red mites. They sometimes look like spiders.

They suck the life out of your plants and are commonly found on azaleas, rhododendrons and roses. Check the plants around your house (in the vicinity of where you found them) - they'll usually be on the underside of leaves or all over the stems. Check leaves for dry, pale patches (not brown) that look like they've had the color sucked out of them.

We usually treat plants with lightly soapy water (dish washing detergent) in an ironing spray bottle and and spray the underside of affected leaves. You can also buy a mite-specific spray from gardening/hardware shop which works well and doesn't harm your plants. You do have to repeat this every few months though - they're stubborn little buggers and will come back after a while!