20 



pressed. Legs with brushy hairs beneath the femora; the tarsi all studded be- 

 neath with minute reddish spines, the hind and middle tibiae still more strongly 

 spined and each with a pair of more prominent spine-like apical spurs, of equal 

 size and hardly longer than the other spines in 3 and not longer than the 

 diameter of tibiae in 9 ; the front tibiae unarmed, the nodule on the inner apical 

 third ovoid and dark ; tarsal claws with a very small pulvillus between them ; 

 front femora 5.5 mm. long; tibiae rather more than half as long; tarsi as long 

 as femora ; middle femora 7.4 mm. long ; tibiae and tarsi but slightly shorter ; 

 hind femora same length as front ones; tibiae 1/5 longer. Wings, with the 

 scales, small, but mostly long, narrow and dense, with long hair at base super- 

 iorly and with the general shape and venation of Hesferia, the primaries with 

 the apical angle more acute, but less so than in Thymele; anal angle not pro- 

 duced but rounded ; secondaries narrow and more rounded than in any other 

 Hesperid genus known to me ; veins quite stout. Abdomen $ very stout and 

 heavy, thickening behind, blunt at tip and truncate below ; $ more slender, and 

 gradually tapering." 



Mabille's definition is shorter and more modern but not nearly so 

 exact : 



"Antennal club fusiform, gradually swelling from base to apex, very obtuse, 

 terminating in a point, which replaces the hook. Primaries with costal margin 

 longer than inner margin ; vein 5 bent downward at base and very close to 4 ; 

 vein 12 terminating before the end of cell ; vein 3 well before the angle and 2 

 a little below the middle. Secondaries with vein 5 feeble and closer to 4; veins 2 

 and 3 approached and situated at the end of the cell. Body very long, stout, ex- 

 ceeding by a good deal the secondaries. Hind tibiae without hair or spurs. The 

 palpi are almost cylindrical, flattened anteriorly, appressed, but not ascending; 

 the third joint is scaled, scarcely visible." 



Both the above definitions are subject to slight criticism. Riley's 

 is too detailed, and while excellent when applied simply to yuccae, 

 must be somewhat expanded to include the other species, especially 

 the portion that deals with the squammation. 



Mabille's definition is inaccurate; as pointed out already the body 

 does not greatly exceed the secondaries, nor are the hind tibiae with- 

 out spurs ; we consider also that the palpi are distinctly upturned or 

 else they could hardly be appressed, the front of the head being 

 rounded; this, however, is a minor point and due probably to a dif- 

 ferent interpretation of the word "ascendant." 



We have already pointed out in our discussion of the preceding 

 genus the structural features peculiar to Megathymiis. The genus may 

 be divided into three groups: (i) those with rough hairy squamma- 

 tion, approaching liesfieriaris in this and also in wing pattern {ueu- 

 moegeni, aryxna, polingi) ; (2) those with closely appressed thoracic 

 clothing, the typical section {yuccae, ursns?, cofaqui?) ; (3) those 



