The following information and list of exemplary links for each non-insect arthropod group was developed by a high school student working as part of the Bugscope Operations Team.

Order Isopoda - Pill Bugs, Sow Bugs

These animals are under the phylum crustacea. The most well known member of this order is the pill or sow bug, the little bug that can roll up into a ball.
Isopods are dorsoventrally compressed (they're more wide than tall).
Though the pill bug is terrestial, most isopods live in the water and have gills on their anterior abdominal appendages. The thoraxes of these animals make up most of the body and usually have 7 pairs of legs.

Links:
Biology of Isopods http://www.mov.vic.gov.au/crust/isopbiol.html
What About Pill Bugs? http://www.winsomedesign.com/Shrub_Steppe/Pillbugs.html
Isopoda http://phylogeny.arizona.edu/tree/eukaryotes/animals/arthropoda/crustacea/isopoda/isopoda.html
Isopods http://www.univaq.it/~sc_amb/isopgen.html

Order Decapoda - Crabs, Crayfish, Lobsters, Shrimp

This order of crustaceans contains the most well known members of the crustacean subphylum. Lobsters, crayfish, crabs and shrimp all fall under this category.
Members of htis order have a carapace, a large fused piece of protective exoskeleton, that covers their entire thorax.They have five pairs of leg-like appendages. The first pair is often actually a pair of claws. Abdomens may be very pronounced (lobsters) or almost non-existent (crabs).

Links:
Fiddler Crabs http://life.bio.sunysb.edu/ee/msr/Uca/
Land Crabs of the Saychelles Islands http://www.geocities.com/RainForest/Canopy/5280/
Lobsters http://octopus.gma.org/lobsters/index.html
Spiny Freshwater Crayfish http://www.nativefish.asn.au/spiny.html
Brine Shrimp and Ecology of Great Salt Lake http://wwwdutslc.wr.usgs.gov/shrimp/shrimp.html

Order Scorpiones - Scorpions

These members of the class arachnida are widely known. They have five pairs of legs including two claw like appendages in front. The tail end of the
cephalothorax has seven segments and the abdomen has five with a stinger at the end. On the underside of the second segment in the tail there is a pair of
comblike structures called pectines whose function is not known. Scorpions have a pair of eyes on their midline (back) and between two and five on their lateral margin.
Scorpions are nocturnal and prefer warm, dry climates. They feed on insects and spiders by catching them with their pedipalps (claws) and sometimes stinging as well. A unique feature of scorpions is that their young are born alive, not as eggs. For a period immediately after birth they are carried on the mother's back. It may take several years for a scorpion to reach adult hood.

Links:
The Scorpion Emporium http://wrbu.si.edu/www/stockwell/emporium/emporium.html
Scorpiones http://www.ucmp.berkeley.edu/arthropoda/arachnida/scorpiones.html
Scorpionida http://wrbu.si.edu/www/stockwell/phylogeny/scorpionida.html

Order Phalangida - Daddy Longlegs, Harvestmen

These arachnid members go by the common names of 'daddy longlegs' or 'harvestmen'. They are not true spiders. One important difference is that phalangids have only one oval shaped body segment. They have two eyes. They have scent glands that secrete a peculiar smelling fluid when disturbed. Some are predators and some are scavengers or plant eaters. Most species live for a year or two.

Links:
Harvestman - Opiliones http://www.xs4all.nl/~ednieuw/Spiders/Opiliones/Opiliones.htm
Daddy Long Legs http://powerup.com.au/~glen/daddy.htm
Harvestmen http://members.aol.com/opilion/QandA.html

Subphylum Trilobita - Trilobites

This extinct group of arthropods lived in the Paleozoic era. They were flattened like isopods and had three distinct divisions of the body. They had a pair of antennae and their appendages were all similar and leglike.The front of their bodies were covered by a carapace (see Decapods). Trilobites were marine animals.

Links:
Virtual Reality at the NHM http://www.nhm.ac.uk/museum/tempexhib/VRML/pictures.html
Introduction to the Trilobita http://www.ucmp.berkeley.edu/arthropoda/trilobita/trilobita.html
Trilobites http://www.paleoart.com/russian_fossils/TR_Sale.htm
Kevin's Trilobite Homepage http://www.ualberta.ca/~kbrett/Trilobites.html
Trilobites.com http://www.trilobites.com/

Class Diplopoda - Millipedes

Belonging to Phylum Arthropoda, Millipedes are long wormlike creatures with many legs. Most have 30 or more legs with most body segments having two pairs per segment. The body, which is cylindrical, has short seven-segmented antennae and compound eyes. Millipede mouthparts are mandibles, and under the mandibles is the characteristic liplike structure: gnathochilarium. This structure is divided into many areas and is often used to identify different millipede groups.

Millipedes generally reside in dark damp places such as in moss, under leaves, and in soil. Some species give off a putrid fluid through openings in the body. This fluid has been found to kill insects when placed in close vicinity to the millipede. While most millipedes are scavengers a few have been found to attack living plants and fewer still are predacious. These creatures overwinter as adults and their eggs are laid during the summer. Baby millipedes begin with only three pairs of legs and gain the others after several molts.

Links:
Diplopoda http://www.oit.itd.umich.edu/bio108/Arthropoda/Diplopoda.shtml
Introduction to the Myriapoda http://www.ucmp.berkeley.edu/arthropoda/uniramia/myriapoda.html
The Diplopoda (Millipedes) http://www.insect-world.com/main/diplopoda.html

Class Chilopoda - Centipedes

Centipedes, also belonging to Phylum Arthropda, are similar to millipedes. Both are elongate and flattened, however, centipedes have only one pair of legs per body segments and have 15 or more pairs of legs. A centipede's final pair of legs is directed backwards and is different from the other legs. Antennae are long and consist of 14 or more segments. Some centipedes have eyes while others do not. Like millipedes, the centipede mouthparts are mandibles. They have two pairs of maxillae with the second pair appearing leglike. A centipedes fist segment has clawlike appendages that act as poisonous jaws.

Centipedes are generally found in unprotected areas such as in the soil or under logs. They are quick and feed on insects, spiders, and other small animals. They all possess the poisonous jaws which are used to paralyze their prey. Centipedes also overwinter as adults and lay their eggs in the summer.

Links:
Chilopoda http://www.oit.itd.umich.edu/bio108/Arthropoda/Chilopoda.shtml
Introduction to the Myriapoda http://www.ucmp.berkeley.edu/arthropoda/uniramia/myriapoda.html
Centipede http://www.ext.vt.edu/departments/entomology/factsheets/centiped.html
Chilopoda (Centipedes) http://www.insect-world.com/main/chilopod.html

Order Acari - Ticks and Mites

This order (Phylum Arthropoda) encompasses a large group of small to minute animals. These creatures are oval with little or no differentiation between body segments. The larvae (newly hatched young) have three pairs of legs and attain their last pair after their first molt.These creatures are found virtually everywhere in both aquatic and terrestrial areas. Acari are most abundant in the soil where they outnumber other arthropods. Most are predacious and attach to the outside of their vertebrate or invertebrate hosts. Others are scavengers that break down forest litter and some are plant feeders which harm crops. Ticks and Mites are known to be pests to humans as they spread disease. Ticks are larger than most Acari and are parasitic to mammals, birds, and reptiles. They are the most important carrier of disease for animals and are second to mosquitoes for humans. These diseases include Rocky Mountain Spotted Fever and Lyme disease.

Links:
Background Information on the Biology of Ticks http://entomology.ucdavis.edu/faculty/rbkimsey/tickbio.html
Ticks http://www.ent.iastate.edu/imagegal/ticks/
Acari - The Mites http://phylogeny.arizona.edu/tree/eukaryotes/animals/arthropoda/arachnida/acari/acari.html

Class Merostomata - Horseshoe crabs

Horseshoe crabs (Subphylum Chelicerata) get their subphylum name from the fist pair of appendages which are chelicerae. The rest of the appendages are leglike and function as jaws. Horseshoe crabs have two regions, the cephalothorax and the abdomen. Horseshoe crabs are the marine form of class Merostomata. They are common along the Atlantic Coast from Maine to the gulf of Mexico and can be found in shallow water in sandy or muddy areas. These creatures feed on marine worms and are identified by their oval shell and spinelike tail.

Links:
Merostomata http://www.oit.itd.umich.edu:80/bio108/Arthropoda/Merostomata.html
The Horseshoe Crab http://www.marinelab.sarasota.fl.us/WHORSESH.HTM
Horseshoe Crabs http://www.cyhaus.com/marine/hcrabs.htm
Horseshoe Crab http://www2.gasou.edu/cturtle/0788limu.html

Order Araneae - Spiders

Belonging to Phylum Arthropoda, Spiders are a widespread and abundant group. Their bodies consist of the cephalothorax and the abdomen. The cephalothorax supports the eyes, mouthparts, and legs while the abdomen bears the genital structures, spiracles, anus, and spinnerets. Most spiders have eight or fewer eyes and all of them are simple. The number and placement of eyes can be used in identification.

Spiders have poisonous glands which open from the chelicerae. Although all spiders have venomous glands, they are rarely harmful to humans. In fact, only a few species in the United States are considered dangerous. Spiders also have pedipalps which are located behind the chelicerae and are clubbed in male spiders. Spiders have seven-segmented legs and most have two or three claws. Characteristic bristles and hair on the legs is often used inidentification. At the end of the abdomen are six fingerlike structures called spinnerets. This is where the silk of the spider is spun. This silk is used to spin webs and create sacs where the eggs are laid.

The females tend to be much larger than the males and in some cases eat the males after mating. All spiders are predacious and eat mainly insects. The victims are generally killed by the injection of poisonous venom.

Links:
Araneae http://www.ucmp.berkeley.edu/arthropoda/arachnida/araneae.html
Araneae, Spiders of North-West Europe http://www.xs4all.nl/~ednieuw/Spiders/spidhome.htm
Class Arachnida http://naturalpartners.org/InsectZoo/Students/araneae.html
Spiders - Eight Legs and Silk http://192.206.48.3/collect/spider2.html