Se 
iid te 
83 
NOTES ON SOME LITTLE-KNOWN INSECTS OF ECONOMIC 
IMPORTANCE. 
By WILLIS G. JOHNSON, College Park, Md. 
I present herewith some notes on seven little-known injurious insects 
that have come under my observation during the past year. 
Hydrecia marginidens.—The first is a moth belonging to the little- 
understood genus Hydrecia (Gortyna). Dr. J. B. Smith, who kindly 
examined my specimen, says: ‘¢ [ have never had sufficient material to 
make me feel satisfied as to the limitation of species. It is one of those 
genera in which the species vary, not only in ground color, but in the 
presence or absence of white spots. It may be mouse-gray with white 
spots, or it may be either of the ground colors without any white spots, 
and yet be the same species. Just what range of variation there is in 
the lines we do not know. It would be a desirable thing to breed a 
large lot of specimens from some one plant in order to get the range of 
variation, if possible. As material goes, your species is marginidens, or, 
as it used to be called, limpida.” 
I found the larva boring into the main stems and larger branches of 
Cosmos plants (Cosmos bipinnatus) at the Maryland Agricultural Experi- 
ment Station. Two larve were obtained from the heart of the main 
stem of a plant August 22,1896. All the branches had been burrowed 
out, so weakening them that they were easily broken off. In fact, a 
slight wind readily broke the plants, and it was this condition that first 
attracted my attention. The two larve were placed in a breeding cage, 
where one of them pupated August 25, The other one died August 27, 
and wasremoved. The adult insect emerged September 30,1896. The 
Cosmos plants have been attacked by the same insect this season, but 
not tosuch an extent as last year. The hollowing out of the stems and 
branches does not seem to injure the plants, so far as growth and bloom- 
ing is concerned, the difficulty arising from the weakening effect indi- 
cated above. 
Pyrausta ferrugalis.—1 found the larva of this beautiful little moth 
injuring the young, tender, lower leaves of tobacco in a hotbed here at 
the station. The larvee were abundant from July 1, feeding usually on 
the underside of the leaves, cutting them full of irregular holes. 
When full-grown, many larve would cut two slits in the side of a leaf, 
fold it over, and pupate within, while others would transform between 
the leaves that happened to be close together. The moths emerged in 
my breeding cages from July 6 to July 13, the greatest number having 
appeared July 9. They were most abundant on plants in the beds 
July 13. They hide on the underside of the leaves and are easily dis- 
turbed, flying quickly when approached, and running rapidly to the 
underside of the leaf when alighting. 
Uranotes melinus.—WhMe examining some lima beans July 13, 1897, 
growing at the experiment station, I discovered two somewhat slug-like 
larve cutting holes into the pods and feeding upon the beans. One 
