152 PROC. ENT. SOC. WASH., VOL. 23, NO. 6, JUNE, 1921 



supreme importance, enabling the separation and definition of 

 closely allied species that otherwise would be difficult or im- 

 possible to separate and also proving beyond dispute the 

 specific identity of varieties, the superficial differences of which 

 obscure their specific limits. With the aid of genitalia the 

 identity or non-identity of a supposedly introduced species can 

 be definitely ascertained, and a question of synonymy settled. 

 No longer need it be a matter of personal opinion. It can be 

 proven or disproven. For example, the identity of Laspeyresia 

 molesta Busck with the Japanese and Australian Peach Moth is 

 thus established while the hitherto accepted identity of the 

 American and European pea moths (L. nigricana Stph. and L. 

 novimundi Heinrich) is disproven. Except for the genitalia 

 both of these cases and many similar ones would have remained 

 debatable. 



The introduction of the male genitalia into the classification 

 of the Microlepidoptera does not in any way invalidate or 

 revolutionize our present well-founded system. On the con- 

 trary, it gives us a better understanding and a surer confidence 

 in this very system, substantiating it, enlarging upon its founda- 

 tions and giving added light where venation is insufficient. 

 The use of genitalia together with characters of the larva and 

 pupa brings us nearer to that ideal of the systematist, a classifi- 

 cation based upon the whole insect. 



EXPLANATION OF PLATES 1 

 Plate XII 



Fig. 1 Male genitalia of 'Sparganothis pilleriana Schiffermuller. 

 Fig. 2 Male genitalia of Peronsa cristana Fabricius. 



Plate XIII 



Fig. 3 Male genitalia of Cerostoma vittella Linn. 

 Fig. 4 Male genitalia of Platyedra vilel/a Zeller. 



Ae aedoeagus. 



An anellus. 



Ca costa. 



Cn cornuti. 



Cs cucullus. 



Gn gnathos. 



Hp harpes. 



Sc sacculus. 



Si socii. 



Tg tegumen. 



Ts transtilla. 



U uncus. 



Vm vinculum. 



Vp ventral plate. 



'The drawings were made by Miss Eleanor T. Armstrong under the direction 

 of the authors. 



Actual date of publication June 22, 1921 



