ART. 19. MOTHS OF THE GENUS DIATKAEA DYAE AND HEINKICH 3 



elements (slight projections from costal bases of harpes). Anellus 

 a flattened or semitubular plate, often with strongly developed lateral 

 arms and sometimes a central projection; sometimes hinged to 

 harpes {Argyria, Silveria) ; frequently divided, with one element 

 represented as a triangular or oval plate (juxta) lying between the 

 bases of the sacculi of the harpes. Aedoeagus straight or but 

 slightly bent, moderately long ; with slight blind sack ; cornuti usually 

 present, variously developed but never deciduous. 



Female genitalia with ductus bursae normally straight; rarely 

 sigmoid {Onvmatopteryx) ; short or moderately long, and chitinized 

 at or toward genital opening. Ovipositor never aculeate, rarely 

 telescopic. Genital plate when present simple, often absent. 



In preparing slides of crambid male genitalia it is usually neces- 

 sary to dissect the several parts and mount them in different posi- 

 tions. The characters of harpe, vinculum, and anellus show best, as 

 a rule, spread and viewed ventrally; while the tegumen, uncus, and 

 gnathos must often be viewed laterally or from a three-quarters 

 projection to show distinguishing characters to the best advantage. 

 We have therefore figured the male organs as dissected rather than 

 complete ; giving such views of the several parts as will best display 

 their characters. The peculiarities of position in each case are stated 

 in the explanation of plates. 



In description of the parts we have followed the terminology pro- 

 posed by Busck and Heinrich ^ and used by them in previous papers 

 dealing with lepidopterous genitalia. 



LARVAE 



Only six of the 56 species here treated are represented by larvae 

 in the National Collection. These are all in the genus Diatraea {sac- 

 charalis, zeacolella, canella.^ grandioseUa^ magnifactella, lineolato)) ; 

 and two of these {magnifacteUa and lineolato) are of doubtful deter- 

 mination. It is not possible therefore to give anything in the way 

 of a larval classification ; nor even a satisfactory specific description 

 which will certainly identify any of the represented species. In 

 another place ^ the junior author has given descriptions of the larvae 

 of our two economically most important North American species 

 {saccharalis and zeacolella) ; but these descriptions will only serve 

 to distinguish the forms described from each other. The various 

 Diatraea larvae vary so little from species to species and the seasonal 

 dimorphism is so marked within each species that it is necessary 

 to have more material before specific characters can be determined. 



1 Proc. Ent. Soc. Washington, vol. 23, June, 1921, pp. 145-152. 



2 Bull. 746. U. S. Dept. Agr., 1919. 



