August, '15] 



CRUAIB: TOBACCO CUTWORMS 



393 



If the necessary cooperation can be secured, the writer wishes to 

 undertake the preparation of a much more extensive cutworm key in 

 w^hich all our economic species might find a place. To this end material 

 from all parts of the country, and especially live larvae in considerable 

 series, is very much desired; and determinations will be made when 

 possible. 



A Key to the Cutworms Affecting Tobacco 



Paraclypeal sutures not attaining apex of head shield (Plate 20, fig. 2). Skin 



smooth, excepting in Mamestra renigera (PI. 20, fig. 10) 2 



Paraclypeal sutures attaining apex of head shield (PI. 20, fig. 1). Setigerous 

 tubercles rather large, distinct. Tubercle IV of abdominal segments very 

 large (PI. 20, fig. 4, IV). Skin granulose (PI. 20, figs. 5, 8, 9, 11) 11 



Head shield clear brown with solid dark fuscous above. Paraclypeal region 



white (PI. 20, fig. 12) 3 



2 \ Fuscous coloring of head shield limited to arcs and reticulation or absent 

 (PI. 20, figs. 6, 7). Paraclypeal region concolorous with remainder of head 

 shield or merely pale, never white 4 



Subdorsal black spots of mesothorax as large as those on seventh abdominal 



segment Prodenia commelince S. & A. 



Subdorsal black spots of mesothorax absent or smaller than those on seventh 

 abdominal segment Prodenia ornithogalli Guenee 



Mandibles each with about 4 teeth 5 



Mandibles with cutting margin straight, toothless or bearing about twelve 

 minute teeth Peridroma incwis Guenee. 



Tubercle IV of abdominal segments distinctly larger than tubercles I, II and 



III. Spiracles black Mamestra meditata Grote. 



Tubercle IV of abdominal segments of about the same size as tubercles I, II, 

 and III .6 



Skin coarsely granulose dorsally. Tubercles I and II conical and bearing 



prominent bristles (PI. 20, fig. 10). Spiracles black 



Mamestra renigera Stephens. 

 Skin smooth, neither shagreened nor granulose. Tubercles and their setse 

 minute 7 



Body without spots but prominently striped. Ground color of head shield 

 white, submedian arcs and stemmatal stripe united posteriorly and at 



maxillary palpi Mamestra legitima Grote. 



Body usually bearing black spots and never prominently striped 8 



With triangular black subdorsal markings, at least posteriorly 9 



Black subdorsal markings linear or absent. Spiracles black. With distinct 



yellow middorsal dots on abdominal segments, at least anteriorly 



Peridroma saucia Hiibner. 



Without black spots above spiracles. Spiracles yellowish with dark rims. 



Ground color of head shield greyish or whitish. Dorsum drab 



Noctua c-nigrum Linnsenus. 

 With distinct black spots above spiracles 10 



