Distribution:- limulus polyphemus, the American horse-shoe crab, is restricted to North-western Atlantic coast,Gulf of Mexico and West Indies. All the other membranes are found along the south east Asian pacific coasts,from Japan and Korea through the East Indies and philippines.
Habit and Habitat:- limulus is a marine Form, found by rrowing in the sand. They live comparatively in shallow water along sandy and muddy shores of sheltered bays and estuaries.
1) Limulus is commonly known as king-crab.
2) Prosoma is covered by an unsegmented, semicircular, or horse-shoe-shaped carapace.
3) Prosoma in conves above with sloping sides and bears three longitudinal ridges one median and two lateral.
4) The metasoma is much reduced.
5) Respiration by book-gills.
6) Larva trilobite.
7) Excretion by coxal or brick red glands.
Distribution:- Forficula is an insect of tropical countries, but it is abundantly found throughout palearctic region Asia, Africa, Europe, Mexico, North America.
Habit and Habitat:- Forficula is commonly found in moist places under stones undecaying vegetables matter etc.
1) Forficula is commonly known as earwig.
2) Body in elongated and covered by a tough chitinous covering.
3) The body is divided into the head, thorax and abdomen.
4) Head bears a pair of eyes and a pair of long Filiform antennae.
5) Mouth parts biting and chewing type.
6) Thorax bears three pairs of walking legs and two pairs of wings.
7) Ovipositor absent. Metamorphosis gradual.
8) They are nocturnal and feeding on vegetation
1) The specific smell of earwigs may have some importance as a defense mechanism, but also plays a role as an attractant for parasitoids.
2) Damage the blossoms of ornamental plants by chewing.
3) Cause economic losses in Fruits and Vegetables crops.