Question

What is the name of the structure which helps the mandibles and function as an accessory jaw?
A. Maxillae
B. Galea
C. Lacinia
D. Labial Palp

Answer 1

Hint: All these structures stated above in the question are present in cockroaches. In cockroaches, the anterior end of the head bears appendages which form the biting and chewing type of mouth part. The mouthparts present in them consist of a labrum, a pair of mandibles, a pair of maxillae, and a labium.

Complete answer:
Maxillae help the mandibles and function as accessory jaws.
In cockroaches, the maxillae are paired structures present behind the mandible in the mouth region. Maxillae are sharp point like structures which act like pincers. They hold the food inside them so that it can be chewed and sliced by mandibles.
Mandible has two regions- The grinding region and Incising region for biting and chewing the food.
Galea is a part of maxilla in cockroaches.
Lacinia is found in cockroaches. In cockroaches, Galea and Lacinia form part of the maxilla. The galea is present outside and acts as a cover while the lacinia is present inwards and consists of teeth that help in chewing of food.
Labial palp- The labium of the cockroach is also known as the lower lip. It is formed by the fusion of the second pair of maxillae.
Labium has a pair of 3-segmented labial palps on either side, acting as a sensory organ and helping them in selecting food. The labium, along with the labrum help to hold the food between maxilla and mandible while grinding

Note:
Cockroaches, also known as Periplaneta americana, are included in the class of insects of Phylum Arthropoda. They are nocturnal omnivorous animals. The body of the cockroach is segmented and divisible into three regions- Head, Thorax, and Abdomen.