This is a collection of some of my favorite websites – Mostly pages devoted to specific subjects that I’ve bookmarked at some point in time. These links will be organized a bit more in coming days!

Arachnids:
Spider Myths – A number of articles by Rod Crawford, Arachnologist at the Burke Museum of Natural History and Culture.
Spider Resources –  Additional links collected by Rod Crawford
Arachnids of Ecuador – A relatively new site with incredible illustrations of Ecuadorian arachnids. A working checklist.
The Spider Guide of South Africa – A guide to the spiders of South Africa, with photos, illustrations and lots of information.
Wandering Spiders (Ctenidae) – An extensive website covering the wandering spiders of the Amazon, primarily in Brazil. Treasure trove of photos, information, etc.
Elias Lab – Animal Communication and Behavior – (Featuring Salticid mating displays)
Pholcidae – Huge resource on ‘Cellar Spiders’ – A wealth of data and a tremendous amount of photos.
Classification of Opiliones – Featuring a huge list of harvestmen species found all over the world, including photos.

Flies:
The Crane Flies of Pennsylvania – Resource provided by the Carnegie Museum of Natural History
Hover Flies – All about Hover Flies – Information, photos.

Butterflies and Moths:
Butterflies and Moths of North America – Collecting and sharing data
Moths and Butterflies of Europe and North Africa – Same as the link above.

Springtails:
Checklist of the Collembola of the World – Photo gallery, keys, and a wealth of detailed information. (Springtails are a favorite subject for me, and one of the main reasons I want to refine my reversed lens setup!)

Crickets and Katydids:
Crickets North of Mexico and Katydids checklist –  Photos, Checklists, lots of resources to subfamilies.

Millipedes/Centipedes:
Millipedes and Centipedes –  The best resource, full of fascinating pages.
Millipede Anatomy – Invertebrate zoology, with labeled figures and descriptive writing.

Gastropods:

Molluscs – Snails, Slugs, bivalves and other molluscs information.
Helicinidae – Dr. Ira Richling’s website about the helicinidae family of snails.
Neotropical Land Snails – Bram Breure’s older snail resource.

Birds:
Beginner’s Guide to Birdwatching – Lots of great tips and resources for the budding birder. 
The Cornell Lab of Ornithology – Bird Identification Guide. Photos, life histories on each bird, range maps, etc.
Xeno-Canto – ‘Sharing bird sounds from around the world’ – Audio clips of bird calls. Awesome and useful.

Amphibians and Reptiles:
Tropical Herping – A website devoted to the reptiles and amphibians of Mindo, Ecuador. Excellent photo gallery, species information and even audio clips.
Amphibians and Reptiles of Italy – Photos, data, easy to navigate.

Whales & Various Cetaceans:
Orca Network – Non-Profit Organization working to raise awareness in the PNW. Their focus is on whales.

Multiple Subject Resources:
Bowerbird – Australian biodiversity site, where people upload photos for identification by experts. For example, Flatworms
The Tree of Life Project – Huge collection of information, a collaboration between naturalists and biologists.
Discover Life – A massive online collection – ID resources about animals, plants, insects, etc. You’ll get lost in here (in the best kind of way!)
Bugguide.net – Online arthropod community for naturalists – Covers the USA and Canada. Photos and taxonomic information.
Smithsonian Research Centers – And research programs.
Kimball’s Biology Pages – Biology textbook, available online.

Space and Space Weather:
Spaceweather.com – A favorite website of mine for many years. Aurora updates, Solar Flares, Near Earth Objects, etc.
Atmosphere Optics  – Atmospheric light formations, this website explains how they form.

Nature/Science Programs:
PBS Video – Nature Documentaries – Free streaming documentaries from PBS.
NOVA – Science Documentaries – Topics ranging from technology, physics, environmental issues, history, etc.