3 



the Deltoids, correspond Avith Prof. Packard's " Noctnelitae." The 

 Deltoids however agree with the Noctuae in the presence of but 

 two internal veins (1 and 1 a) on the hind wings, Avhereas the true 

 Pyralids have three. I have treated them as a sub-group of the 

 Noctuae, as also Prof. Packard's Noctuinae and Gatocalinac. 



Several species of Noctuidae, belonging to the genera Agrotis, 

 Iladena and Mamestra, are interesting to Economic Entomology 

 from the depredations they commit upon cultivated plants. In 

 the various State Keports on Insects Injurious to Vegetation, I 

 have not noticed any appreciation of the structural characters that 

 separate these genera. The perfect insects belonging to the three 

 genera nearly agree in palpal structure, in the proportionate wings 

 and in the absence of scale tufts on the front or vertex of the head. 

 They differ as follows : 



Eyes naked, without lashes. Thorax without divided dorsal longitudinal, 

 or posterior scale tuft ; abdomen untufted. Middle and hind tibiae always, 

 fore tibiae sometimes, with spines Agrotis. 



Eyes naked, without lashes. Thorax with divided dorsal longitudinal and 

 posterior tufts ; abdomen more or less distinctly tufted. All the tibiae un- 

 armed Hadena. 



Eyes hairy. Thorax with dorsal and posterior tufts; abdomen more or less 

 distinctly or entirely tufted. All the tibiae unarmed Mamestra. 



Minor divisions are established on the details of antennal struc- 

 ture and the form of the genital pieces. 



The subject of geographical distribution is one of very high im- 

 portance to a proper understanding of our American Noctuidae ; 

 those species indicated by a star (*) in the present List are consid- 

 ered to occur both in America and in Europe. "Where the genus is 

 represented in the European fauna, the same mark is affixed to the 

 generic title. Below each genus the geographical distribution in 

 North America is approximately indicated. 



There will be found in the List the names of a number of species, 

 for the most part excellently described by M. Guenee, in the Species 

 General, which are yet unidentified in our collections; to these 

 a dagger (f) is prefixed. The same sign precedes nearly all the 

 names taken from the British Museum Lists ; unfortunately there 

 is no present prospect that these latter will become available, 

 although but few of Mr, Walker's descriptions are not referred to 

 here. 



