I'm going to start compiling diagnostic web photos... I'll work on the article portion later.
Webs For Hunting
Orb Webs
Orb Weavers (Araneidae)
Araneus
Larinia borealis - note the 'droopiness' of the web - not sure if this is diagnostic
Metepeira - above and to one side is an irregular tangle of threads called a barrier web, and this is where the spider builds its retreat. (1)
Zygiella - missing sections is diagnostic
Argiope aurantia - web usually has vertical zig zag bands also known as stabilimentum - may be more zig zags if made by a juvenile
Argiope argentata / florida (zig zag bands usually diagonal)
Argiope trifasciata - less zig zags noticed for this species
Mangora gibberosa - like the Argiopes I believe the stabilimentum is used more by juveniles
Spined Micrathena (Micrathena gracilis)
Gasteracantha cancriformis - note the tufts on the silk, and the green egg sac
Allocyclosa - vertical line of egg sacs above the spider, debris below.
Cyclosa - vertical line of debris
Ray Orb-weavers (Theridiosomatidae) - These spiders create a web that is attached to a twig in the center of the web creating an umbrella shape (2) (photo of web needed)
Mecynogea lemniscata - Basilica Orbweaver
Bolas Spiders
Nephilidae
Golden Silk Orbweaver (Nephila clavipes)
N. trigonum       A. elevatus       Rhomphaea projiciens
Hacklemesh Weavers - Amaurobiidae
Mesh Web Weavers (Dictynidae)
Webs For Protection & Retreats
Nursery Webs
Nursery Web Spiders - Pisauridae - Webs for protecting egg sacs, not for hunting.
Dolomedes
Pisaurina
Folded Leaf Retreats
Trachelas
Clubiona? - could possibly be a Miturgidae
Miturgidae
Other Retreats
Pirata retreat
Marbled Cellar Spider (Holocnemus pluchei) - Females of this species make a spherical web around themselves and their egg sacs. (3)
No Webs
Wolf Spiders - Lycosidae - Wolf spiders are the only spiders to hold their egg sacs under their abdomen by the spinnerets and carry their babies on their backs. Many wolf spiders never create any type of web other than a drag line, though some create retreats (Pirata above) and others create silk lined retreats in the ground.
Pirate Spiders - Mimetidae - These spiders sometimes invade the webs of other spiders. They often eat the prey they find there. Their egg sacs are on a web stalk.
References:
1. The Insects and Arachnids of Canada, part 23. The Orb-Weaving Spiders of Canada and Alaska. Dondale, Redner, Paquin & Levi. (1)
2. Spiders and Their Kin by Levi & Levi. (2)
3. Tracks & Sign of Insects and Other Invertebrates by Eiseman & Charney. (3)
Look-a-likes
Ichneumon Wasp Cocoon
Mystery to solve:
Contributed by Lynette Elliott on 8 September, 2010 - 3:23pm Last updated 4 February, 2016 - 8:06am