618 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxix. 



of the hind wing.s, which appears to be wanting only in the genus 

 Oryss'us (tig. 07). 



The most notable difference is found in the condition of the base of 

 the radial cross- vein. The radial sector separates from Rj at or before 

 the base of the stigma. This is shown in the wings of Macroxyela 

 (lig. 33) and Cxnolyda (tig. 19, c/), where the radial sector, after sepa- 

 rating from Ri, extends transversely for a considerable distance before 

 extending longitudinally. The radial cross-vein in Macroxyela is a 

 perpendicular vein extending from near the middle of the stigma to 

 near the middle of the cell Rg. In Bactroceros (tig. 41) this cross- 

 vein joins the stigma near its apex and the cell R, near its apex. In 

 the genus TentJiredo (tig. 19, h) the radial sector likewise arises from 

 the base of the stigma, but differs from Macroxyela and Caenolyda in 

 that the base of the radial sector does not extend transverse!}^, but 

 extends from Rj along R, to the margin of the wing in a continuous 

 regular curve. The anterior end of the radial cross-vein is beyond 

 the middle of the stigma, as in Bactroceros^ and the posterior end has 

 migrated to near the middle of the cell R^. Cladius (tig. 19, c) shows 

 a condition similar to that found in TentJiredo^ except that the radial 

 cross vein has atrophied, but it should be noted that in both of these 

 genera — the one with a radial cross- vein, the other without — the radial 

 sector arises in exactly the same manner. In Paururus (tig. 19, d) the 

 radial sector arises in a similar manner to that of Macroxyela and 

 Cmnolyda^ except that the transverse part is not so prominent. The 

 radial cross-vein extends between the apical third of the stigma and 

 the apical third of cell Rr,. It should be noted that this cross-vein is 

 parallel with the transverse part of the radial sector and appears to be 

 the dii-ect continuation of that part of the radial sector bevond it. 

 This appearance is emphasized b\' the position of the posterior end of 

 the radio-medial cross-vein, which has migrated along the base of 

 media until it has come into line with the longitudinal part of the 

 radial sector, so that one not very familiar with the topography of 

 this area might easily make the mistake of considering this vein as 

 arising at the posterior end of the radio-medial cross- vein and the basal 

 or transverse part of the radial sector, as well as the radial cross-vein, 

 as cross-veins. 



The wings of Meyalodontes (tig. 19, e) are shorter and more com- 

 pact, and there has been a crowding of the cells R, Rr,, 1st Rj, and M^ 

 into the area behind the stigma, resulting in a condition similar to 

 that found in Paururus. There are the following differences, how- 

 ever: The transverse part of the radial sector and the radial cross- 

 vein are longer; the cross-vein is more ()})lique, and the appearance 

 that it is the base of R., is more strongly emphasized; and the radio- 

 medial cross-vein appears to lie the continuation of the vein extend- 

 ing f i-om the posterior end of the radial cross-vein to the anterior end 



