Mosquito identification — DTM&H MCQ

Correct answer: B — Anopheles

The correct answer is B, Anopheles. The combination described, spotted (mottled black and white) wing scaling, maxillary palps nearly equal in length to the proboscis, and a resting posture with the body angled at roughly 45 degrees to the surface, is the classic morphological triad used to identify Anopheles in field and diagnostic entomology. This matters clinically because Anopheles is the only genus that transmits human malaria (Plasmodium species) and several species also transmit Wuchereria bancrofti, so correct genus identification underpins vector control and malaria risk assessment taught in UK tropical medicine training. No other genus combines all three features simultaneously, making this a reliable bedside/field discriminator even without a microscope. Why the other options are wrong: C. Aedes: Aedes species have short palps (much shorter than the proboscis), plain or banded (not spotted) wings, characteristic black and white striped legs, and rest with the body parallel to the surface, not at 45 degrees. A. Culex: Culex have short palps, unmarked (plain) wings, and rest parallel to the resting surface, lacking both the spotted wing pattern and the raised abdominal posture. D. Mansonia: Mansonia have broad, dusty-appearing wing scales rather than discrete spotted blocks, short palps relative to the proboscis, and a resting posture that is not angled at 45 degrees. E. Haemagogus: Haemagogus are diurnal, brightly metallic-coloured forest canopy mosquitoes with short palps and a parallel resting position; they are not defined by the palp-to-proboscis equality or the 45 degree stance. Key point: Palps as long as the proboscis, spotted wings, and a 45 degree resting angle together are pathognomonic for Anopheles, the sole genus transmitting human malaria.

Reference: CDC DPDx, Malaria: Biology (Anopheles vector morphology and resting position), https://www.cdc.gov/dpdx/malaria/index.html