978 I. M. Haw try 
(1902) did not find it around Chicago in 1902, tho it had been reported 
from Michigan in 1899. Cockerel!® found agrestis in Colorado in 1890, and 
he states that it was brought there from New Jersey. He reports it also 
in Oregon in 1891 and in California in 1892. 
In western New York the localities infested by A. agrestis are increasing, 
and in wet seasons many beans, as well as other field and garden crops, are 
injured. The insect is apparently not a pest in all sections of the bean- 
growing counties, but appears to be limited to a few farms and gardens in 
each district. Some places seem to be entirely free from it. It is often 
abundant on small truck farms, and around the shrubbery and the gardens 
n city lots. It has, no doubt, been carried into its present habitats in 
the straw or moss packing of bulbs, shrubs, or nursery stock. Dissemi- 
nated in this way, it seems to thrive, and it apparently prefers cultivated 
crops to woods and pasture land. As it becomes better established the 
species may be expected to spread from the present centers of infestation 
until it is of almost general distribution. The long, cold winters often 
experienced in New York, however, should tend to prevent the serious 
damage that it causes nearly every year where the climatic conditions are 
milder and more uniformly moist. 
SYSTEMATIC POSITION 
The field gray slug belongs to the phylum Mollusca and the class Gas- 
tropoda, which includes the slugs and the snails. Agriolimax agrestis is 
placed in the family Limacidae, the members of which have no external 
shell. This family, according to Pratt (1916), is represented in America 
by only six species. The large spotted slugs of the family are now placed 
in the genus Limax L., while smaller forms, such as agrestis, belong in 
Agriolimax Morch. Because of its varied coloration, this slug has been 
described under many specific names. Taylor (1907) gives a complete 
synonymy for the species, and lists ten varieties, with the localities from 
which each has been reported. 
GENERAL DESCRIPTION OF THE SLUGS OF THE FAMILY LIMACIDAE 
The field gray slug belongs to the same group of Mollusca as the snails, 
and differs from them but little except in the size and form of the shell. 
In slugs of the family Limacidae no shell is visible on the outside of the 
body, but there is a thin calcareous plate (Plate LXIX, 5) concealed in the 
mantle — the fleshy shield over the front part of the slug. The body is 
elongate-subcylindrical, and bears a more or less prominent dorsal keel. On 
the retractile head are two pairs of tentacles; the anterior pair aids in feed- 
ing, while the upper, or posterior, pair bears the eyes. The eyes have the . 
form of rounded knobs on filament-like stalks. When the slug is disturbed, 
6 As cited by Taylor (1907:120). 
