Arachnid anatomy

thumb|Collection of hemolymph from a worker honeybee.

excretory and osmoregulatory system

thumb|right|Green-shaded pedipalps in an illustrated dorsal view of a Uropygi|whip scorpion

right|thumb|upright|Earwig with large cerci (top) Cerci (: cercus) are paired appendages usually on the rear-most segments of many arthropods, including insects and symphylans. Many forms of cerci serve as sensory organs, but some serve as pinching weapons or as organs of copulation. In many insects, they simply may be functionless vestigial structures.

type of lung commonly found in arachnids

sex-determination system, with only 1 sex chromosome (“X”); males only have 1 X chromosome (X0); females have 2 (XX); found in most arachnids, many insects, some nematodes, some crustaceans, some molluscs, and some fish (e.g. Ancistrus)

Gland found in some arthropods

thumb|Four trichobothria on the second leg of the spider Paratropis tuxtlensis Trichobothria (singular trichobothrium) are elongate setae ("hairs") present in arachnids, various orders of insects, and myriapods that function in the detection of airborne vibrations and currents, and electrical charge. In 1883, Friedrich Dahl observed that they were deflected by the sound waves from a violin and labelled them 'hearing hairs'.

thumb|Ixodes hexagonus, a [[tick.]] The gnathosoma (from Greek , ' = "jaw" and , ' = "body") is the part of the body of the Acari (mites and ticks) comprising the mouth and feeding parts. These are the hypostome, the chelicerae and the pedipalps. It is also called the capitulum (however, this word also has other meanings). It is separated from the main body of the animal (the idiosoma) by a flexible section of the cuticle called the circumcapitular furrow or circumcapitular suture.