Is Every Vein a Real Vein? Cross-Section of the Wing of Matsucoccus Pini (Insecta, Hemiptera, Coccoidea: Matsucoccidae)

SIMPLE SUMMARY: Wings play an important role in insect locomotion. It is the venation that provides reinforcement to the wings. An important question is whether the lines considered to be veins are visible in cross-section or are they just the folds of the wing’s membrane. The cross-sections of the forewing of the scale insect Matsucoccus pini were cut and confirmed the presence of only one vein—radius. There were also campaniform sensilla described, for the first time, on both the dorsal and ventral sides of the wing base. ABSTRACT: Wings of Matsucoccus pini males were studied. Using light and scanning electron microscopes, both sides of the wing membrane, dorsal and ventral, were examined. The presence of only one vein in the common stem was confirmed by the cross-section, namely the radius. The elements regarded as subcostal and medial veins were not confirmed as veins. On the dorsal side of the wings, a cluster of campaniform sensilla is shown for the first time in the family Matsucoccidae, through SEM, and two additional sensilla were found on the ventral side. There was a lack of alar setae, microtrichia as well as pterostigma. This is the second cross-section of the wing among scale insects. We propose the following nomenclature for the wings in the family Matsucoccidae: subcostal thickening (sct), radius (R), median fold (med) and anal fold (af).