The right and left mandibles and maxillae of bed bugs are four elongated stylets connected at their midlines and this forms the fascicle that penetrates the skin. Its large beak or proboscis (composed of the labium) encompasses the fascicle when not feeding but bends out of the way and only the fascicle penetrates during feeding. Due to their morphology, the right and left maxilla form a large food canal in their center which continues down the length of the connected stylets. A much smaller salivary canal is formed between them on the side closest to the body (when folded in resting position). Credit: Louis Sorkin