Which family has a neck-like head due to a constriction behind the eyes and a beak that folds into a groove in the prosternum?

• A. Coreidae
• B. Reduviidae
• C. Cimicidae
• D. Gerridae

Answer: (B)

The feature being tested is recognizing a distinctive head and rostrum arrangement that identifies assassin bugs. In this family, the head forms a narrow “neck” because the head is constricted just behind the eyes, giving that neck-like appearance. The beak, or rostrum, is used to pierce prey and is typically folded back under the body, resting in a groove on the prosternum when not in use. This combination—a necked head and a rostrum tucked into a ventral prosternal groove—is characteristic of Reduviidae. Other groups here don’t share this exact setup: leaf-footed bugs have different body proportions and hind-leg adaptations; bed bugs are flattened and oval with a different head structure and no rostrum tucked into a prosternal groove; water striders have long legs and adaptations for living on water rather than a neck-like head and rostrum groove.