NO. 1140. NORTH AMERICAN NOCTUIDAE— SMITH AND DYAR. 33 



Group auricoma contains forms in which the male clasper forms a 

 chitinous thickening at the base of the sidepiece, usually separating 

 beyond the middle and forming a straight inferior process and a curved 

 and more slender superior hook, the two diverging from an acute angle. 

 Tlie variation is in the proportion of these two j)roeesses, the lower of 

 which tends to obsolescence. 



Superficially the species divide into two series, one of which is char- 

 acterized by short, stumi)y primaries, with themaculation ofihepersuasa 

 group, the other by long subequal or almost lanceolate forewings, 

 derived out of the tritona type of the lobeliae group. We have also, 

 in the second series, an obvious tendency to a flattened or even retreat- 

 ing front, accomi^anied by a weakened tongue. 



We find, therefore, a diversity of structure in the adults relatively as 

 great as any that occurs in the larvae, and that, similar as the species 

 may seem at first sight, they are so in reality only to him who is con- 

 tent to look at the surface, in dread of disarranging a scale lest the 

 specimen should become thereby less desirable for the cabinet. 



The synonymy has been worked out as carefully as i)ossible and is 

 believed to be correct, though it differs from any heretofore proposed in 

 some respects. None of the Guenc'e or Walker types have been actually 

 compared by the authors, but Dr. Riley's notes contained memoranda 

 of nearly all the species represented in the British Museum, and Dr. 

 Butlers notes on the same sjiecimens were also of much use. Each 

 description was carefully compared, however, and specimens fully agree- 

 ing were in all cases secured. The nan.es heretofore not identified from 

 the "Species General" have all been applied, and here the references 

 to the early stages have in some instances decided the question as to 

 what was really intended. 



SYNOPSIS OF GROUPS. 



Priiuariea well developed, trigonate. outer margin oblique, apices sornevrhat drawn 

 out; all the markiugs usually normal, but teudiug to break up into 

 spots or blotches ou the transverse lines, which are often marked on the 



costa only; psi marks not prominent Group americana. 



Primaries rather abruptly widening on inner margin at base, less obviously trigo- 

 nate, outer margin arcuate, the apices rectangular, or even a little 

 rounded. 

 Vestiture smooth, the markings not picked out by elevated scales ; the dagger 



marks prominent Group lobeliae. ^ 



Vestiture rough or siiuamose, the markiugs picked out by elevated scales. 



Psi marks evident, wing form as in lobeliae Group lobeliae. ^^ 



Psi marks wanting or barely indicated, primaries trigonate, apices rectangu- 

 lar; broader than in lobeliae in proportion to length Gvon-p jjersiiasa. 



Psi marks present or wanting, costal margin arcuate, the i>rimaries widen- 

 ing abruptly near base and subequal Grouj) hamamelis. 



Primaries short, trigonate, stumpy in appearance, or long, narrow, subequal or 

 lanceolate Group auricoma. 



Proc. N. M. vol. xxi 3 



