Regents of the University of Michigan
Animal Diversity Web: Class Merostomata (Horseshoe Crab)
Find general information about the Merostomata class, which includes horseshoe crabs and the extinct eurypterids. Topics include diet, body charactersitics, and respiratory system.
Other
Walking Well: Arthropod Stings
This site has interesting information about stings from different arthropods like bees, wasps, hornets, yellow jackets, ants, caterpillars, spiders, ticks, centipedes, millipedes, and scorpions.
Regents of the University of Michigan
Animal Diversity Web: Phylum Arthropoda
This general overview of the arthropod phylum, which includes insects and arachnids, looks at such topics as body symmetry, appendages, movement, respiratory and nervous systems, and reproduction.