14 



Tangle de la cellule et un peu au-dessus du milieu ; 2 bien plus pres de la base de 

 I'aile et un peu au-dessous du milieu de la cellule. Ailes inf erieures ; nervure 

 5 developpee et bien plus pres de 6 que 4, et courbee a sa base. Discocellulaire 

 formant un angle rentrant et profond. Tibias munis de longs polls flexueux et 

 sans eperons." 



He further remarks "The genus Aegiale of Felder scarcely dif- 

 fers from the following (i. e. M egathymns) . Perhaps it should be 

 united with it, but I have only seen one specimen without body or 

 head." 



Mabille is correct in this last remark, and we were for some time 

 in doubt as to whether it would be possible to separate the two genera 

 on any distinct morphological characters. If one compares the two 

 types of the respective genera, viz. hcsperiaris and yuccae, one would 

 unhesitatingly consider them generically separate. The thoracic 

 squammation of hcsperiaris is very hairy, that of yuccae composed of 

 flat, appressed scales, reminding one as Riley has justly remarked of 

 the Cossid genus Xyleutcs {Prio)ioxystiis Grt.). The antennae of 

 hcsperiaris (PI. IV, Fig. 8) swell gradually from about the 21st joint, 

 and the knob thus formed is long, cylindrical and ends in a minute, 

 slightly bent point; in yuccae (PI. IV, Fig. 7) the swelling is much 

 more sudden, the knob shorter and stouter and the terminal point al- 

 most absent. Unfortunately neither of these features appears to be 

 of generic value; in M. ursus Poling the shape of the antennal knob 

 agrees with hcsperiaris whilst the scaling of thorax, palpi and legs is 

 so distinctly as in yuccae as to preclude all association with hcsper- 

 iaris. Again in the neumocgeni group we have examples of 4 squam- 

 mation mid-way between the two generic types ; all three members of 

 this group are considerably more hairy than yuccae and could very 

 well fall under Aegiale on this score; the antennal knob, however, is 

 exactly as in yuccae. 



The legs offer no distinctive feature; both generic types possess 

 spined tibiae and tarsi and the two posterior tibiae have a single short 

 terminal pair of spurs. This is contrary to the statements of Felder 

 and Mabille and we can only suppose that the long hairy covering on 

 the tibiae concealed the spurs from their view. 



In the venation the 9 9 of both hcsperiaris and yuccae are prac- 

 tically identical; in the $ of yuccae, as already mentioned, vein Cu, 

 is bent considerably downward at its base, approaching Cuj, a special- 

 ization of wing structure supposed to lend more strength to the wing- 



