Question

Plerostigmata is present on forewings of:
(A) Hymenoptera
(B) Psocoptera
(C) Megaloptera
(D) Mecoptera
Choose the correct answer from the options given below:

• A. (A) and (D) only
• B. (A), (B) and (D) only
• C. (A), (B), (C) and (D)
• D. (B), (C) and (D) only

Hint:

The stigma helps prevent wing damage during flight by increasing rigidity at high angles of attack.

Answer 1

The Correct Option is A

Plerostigmata:
Pigmented spot near wing tip
Found in:
Hymenoptera (sawflies, bees, wasps)
Mecoptera (scorpionflies)
Absent in Psocoptera and Megaloptera

Answer 2

Elimination approach:
The pterostigma (plerostigmata) is a thickened, pigmented cell near the leading edge of the forewing tip that adds mass and helps stabilise wing flutter during flight. Insect orders that are largely wingless or weak, fluttering fliers with membranous, unthickened wings, such as Psocoptera (booklice/barklice), typically lack this structure, so option (B) can be excluded. Megaloptera (dobsonflies, alderflies) also generally lack a true pterostigma on their broad, net-veined wings, excluding option (C).
Hymenoptera (bees, wasps, sawflies) and Mecoptera (scorpionflies) are both active, sustained fliers whose forewings characteristically carry a distinct pterostigma.
Eliminating (B) and (C) leaves only (A) and (D).