Question

Plantulae are found in cockroach upon
A. Pretarsus
B. Tarsus
C. Trochanter
D. Coxa

Answer 1

Cockroaches are the members belonging to the phylum Arthropoda. The cockroaches bear three pairs of jointed appendages or legs in the region of the thorax, which are utilized for various activities such as walking, climbing and running. The legs are powerful and each pair is designed to perform a distinct function.

Complete answer:
There are three important regions in which the body of cockroaches can be divided. It can be divided into the head, thorax and the abdomen. The eyes, antennae and the mouth parts are present in the head region. The eyes can be moved and composed of cells that are photoreceptors in nature. They are called as ommatidia. The antenna are movable structures and are sensory in function and are called as the antennal flagella or the feelers. The three pairs of appendages or legs are attached in the thorax region of the body. Depending upon the region of the thorax to which it is attached, the legs are of three kinds, namely the prothoracic legs, the mesothoracic legs and the metathoracic legs.

The prothoracic legs are the shortest legs and they act as brakes and control the organism during running. These types of legs are present close to the head of the cockroaches. The middle legs or the mesothoracic legs are present in the mid portion of the thorax. These legs control the speeding of movement by navigating either backwards or forwards. The last pair of very long types of legs are called metathoracic and help the animal to move forwards.

The different pairs of legs though differ in action, have the identical structural parts and work in the same way. In the structure of the leg, an upper part is present which is called the coxa. It is the point of attachment of the leg with thorax. The remaining portion of the leg is further divided into trochanter, femur and tibia and tarsus. The trochanter helps the leg to bend whereas the femur and tibia are like the thigh bones.

A segmented portion on the leg is known as the tarsus and it acts like the ankle and foot. The tarsus consists of different segments which are pretarsus, plaintulae, pulvillus and terminal claws. In between the tarsal claws the pulvillus are present which are lobes or adhesive pads like structure. The distal part of the tarsus generally bears the claw and is known as pretarsus. On the underside of the tarsal segments, in the region of pretarsus, the plantulae is present. The plantulae remains connected with the pretarsus and it helps the organism in walking or moving over smooth surfaces.

Hence, The correct answer is option (A).

Note: The cockroaches use their appendages or legs to perform different activities like walking, running and climbing. On the basis of structure of legs, legs are divided into three parts. The most terminal part of the leg is called the tarsus. The tarsus bears the pretarsus at its distal part. The pretarsus contains the claws. On the pretarsus, the plantulae is present which helps the animal in movement through smooth surfaces.