Fig. 3. Schematic representation of the average distribution of trichoid hairs on the dorsal surface of a locust forewing (based on N=5 detailed drawings). (A) The principal veins of the forewing, named according to Albrecht (1953). The vannus region of the trailing edge is delineated by the claval furrow (broken line) that lies between the postcubitus and vannal veins. The furrow forms a hinge so that at rest the vannus is folded over the dorsal surface of the animal, i.e. the vannus of one wing overlaps the vannus of the other (see Fig. 5A). (B,C) Average distribution of the three types of hairs on the forewings of female (B) and male (C) locusts. The total numbers were counted per vein in five animals and the mean numbers are indicated here (each colour-coded dot represents one hair). This representation does not reflect the exact locations of hairs in any one preparation. Basiconic sensilla occurred on many of the veins (red dots) whereas medium length hairs occurred in greatest numbers on the subcosta (light blue dots) and long hairs occurred only on the postcubitus (dark blue dots). Black arrowheads indicate long hairs that were counted as part of the wingtip region.