The elements of insect anatomy The elements of insect anatomy : an outline for the use of students in entomological laboratories elementsofinsect00comst Year: 1916 91 There are still other writers who do not regard the costa as a true vein, and, therefore, designate the subcosta as vein I. The result is that there are three distinct systems of numbering the wing- veins, in addition to several old systems which were applied to single orders. It seems better, therefore, to designate the wing-veins by names, and use abbreviations of these names in lettering figures. Names of the cross-veins.—In
The elements of insect anatomy The elements of insect anatomy : an outline for the use of students in entomological laboratories elementsofinsect00comst Year: 1916 91 There are still other writers who do not regard the costa as a true vein, and, therefore, designate the subcosta as vein I. The result is that there are three distinct systems of numbering the wing- veins, in addition to several old systems which were applied to single orders. It seems better, therefore, to designate the wing-veins by names, and use abbreviations of these names in lettering figures. Names of the cross-veins.—In the Diptera and in cer- tain other orders of insects there are so few cross-veins that it is practicable to apply names to them ; these are as follows : The humeral cross-vein.—This is a single cross-vein ex- tending from the subcosta to the costa near the base of the C Fig. 3.—Fore wing of a butterfly with the veins and cells numbered. wing. This is the most constant of all of the cross-veins. It is represented in Figure 2, but is not lettered. The radial cross-veiti.—This is a cross-vein which divides cell R^. (The cells are defined a little later.) The radial cross-vein is not represented in Figure 2. The radio-medial cross-veiti.—This is a cross-vein extending fpom the radius to the media, usually near the center of the wing, and is designated by the abbreviation r-fn. When in its typical position this cross-vein extends from vein R^^^ to vein J/,+j ; this results in one end being opposite cell R^ and the other end opposite cell ist M,^.
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