The veins in both tne lore and hind wings of buttermes may be divided into simple 

 and compound veins. In the fore wing the simple veins are the costal, the radials, 

 the submedian, and the internal; in the hind wing they are the costal, the subcostal, 

 the radials, the submedian, and the internal. The costal vein in the hind wing is, 

 however, generally provided near the base with a short ascending branch, which is 

 known as the precostal vein. In addition to the simple veins there are in the fore 

 wing two branching veins, one immediately following the costal, known as the sub- 

 costal, and the other preceding the submedian, known as the median. The branches 

 of these compound veins are known as nervules. The median vein always has 

 three nervules. The nervules of the subcostal veins branch upwardly and out- 

 wardly toward the costal margin and the apex of the fore wing. There are always 

 from four to five subcostal nervules, variously arranged. In the hind wing the sub- 

 costal is simple. The median vein in the hind wing has three nervules, as in the 

 fore wing. In both wings between the subcostal and the median veins toward the 

 base is enclosed the cell, which may be either closed or wholly or partially open at its 

 outer extremity. The veinlets which close the cell are known as the discocellular 

 veins, of which there are- normally three. From the point of union of these disco- 

 cellular veins go forth the i adials, known respectively as upper and lower, though 

 the upper radial in many genera is emitted from the lower margin of the subcostal 

 veiu. 



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