Invertebrate Zoology

The labella is a complex structure consisting of many grooves, called pseudotrachea, which sops up liquids much like a sponge does. Salivary secretions from the labella assist in dissolving and collecting food particles so that they may be more easily taken up by the pseudotrachea.

The pharyngeal dorsal bulb of the earthworm is a true salivary gland. Thus, salivary glands are found on the pharyngeal wall.

The sac-like glands between the 5^th and 6^th abdominal tergites are called stink glands in cockroaches.

Anopheles mosquitoes can be distinguished from other mosquitoes by the palps, which are as long as the proboscis. In males, 3-segmented maxillary palp is present.

When a body is externally and internally divided into segments with serial repetition of atleast some organs, then it is called metamerism. In earthworm, segments are about 100 to 120 in number.

Leech sucks human blood.

Correct Answer: Ovaries mature first in an earthworm.

In males, in the 9th sternum of abdomen, a pair of small, un-jointed anal styles is present. It is absent in females.

Correct Answer: lung

Leech sucks human blood.

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.