Invertebrate Zoology

A silverfish (Lepisma saccharina) is a small, wingless insect. It is an arthropod. 

Leech sucks human blood.

Earthworm is known as 'friend of farmers'. 

Chloragogen cells in annelids function as a liver in vertebrates. These cells store glycogen and neutralise toxins and are yellowish in colour.

The oriental cockroach, also known as the waterbug, is a large species of cockroach. Its scientific name is Blatta orientalis.

Pheromone is a chemical substance that is produced and released into the environment by an animal that affects the behaviour or physiology of others of its species. It produces a pungent smell in cockroaches.

Moths comprise a group of insects related to butterflies. They belong to the order Lepidoptera.

The nerve cord is ventral in position and runs from the fourth segment all the way to the last segment of the worm. In cockroach, the ventral nerve cord runs along the ventral wall of thorax and abdomen and possesses nine fused ganglia, out of which three are thoracic and six are abdominal in position.

Complete metamorphosis is the total change of an insect that goes through four distinct stages. Those stages are egg, larva, pupa and adult.

A nephric tubule leads from each nephrostome through the septum and into the following segment. This tubule then leads to the main body fluid filtering organ, the nephridium or metanephridium, which removes metabolic waste from the coelomic fluid and expels it through pores called nephridiopores. These are found maximum in the clitellar region as this region is formed by merging two or three segments.

This is the hard, powerful cutting jaw.

The larvae liberated into the small intestine do not directly develop into mature worms. The rhabditiform larvae penetrate the gut mucosa and are carried by the portal circulation to the liver, where they live for 3 to 4 days. Finally, they pass out of the liver and enter the pulmonary circulation through the right heart. In the capillary of the lungs, they grow almost ten times bigger.

Lepidoptera is an order of insects that includes moths and butterflies (both called lepidopterans).

Earthworm has no special respiratory organ. It respires through its skin.

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