Which structure in insects serves as the extended mouth for piercing and sucking, especially in female mosquitoes?

The proboscis in insects, particularly in female mosquitoes, is an essential adaptation for feeding. This specialized structure functions as an extended mouthpart, enabling the mosquito to pierce the skin of its host and access blood, which is crucial for egg development in females. The proboscis is elongated and equipped with a set of stylets, which are sharp, needle-like structures that allow it to penetrate the skin.

The anatomy of the proboscis facilitates a dual purpose: it acts as both a piercing tool and a channel for the intake of blood. When a mosquito lands on its host, it first uses the proboscis to locate a blood vessel and then inject saliva, which contains anticoagulants to prevent clotting, allowing for a steady flow of blood while it feeds. This feeding mechanism is a significant reason why female mosquitoes are vectors for various diseases, as they can transmit pathogens during the blood meal.

In contrast, the other terms provided do not describe the feeding structure of mosquitoes. The prosoma refers to the front part of certain arachnids, chelate pertains to claw-like appendages often associated with crustaceans or certain insect mouthparts, and palp generally refers to sensory or feeding appendages that assist in handling food or sensing