INSECTS AND OTHER ANIMAL Pests InNJuRIOUS To FIELD BEANS 985 
countless. Slugs thrive in sod land and many eggs may be found in the 
spring around the roots of grass in fence corners and in meadows. 
One pair of field gray slugs may deposit from 500 to 800 eggs, according 
to Theobald (1905). This writer says that the eggs are given out in batches 
of about 50 at a time, cemented together in piles of from 6 to 15. Taylor 
(1907) cites a case in which a pair of agrestis deposited 774 eggs during the 
season, and Lovett and Black (1920) found 612 eggs deposited by one 
specimen between May and the following April. One slug, found by the 
writer early in the spring, deposited 180 eggs between May 5 and June 
19. Two slugs confined in one cage have produced as many as 464 eggs 
before they died, and it is probable that, due to cage comichiplons, this was less 
than the normal number. 
Many eggs of A. agrestis do not hatch. After the severe winter of 1917, 
the writer was unable to find a single egg in the spring where there had 
been thousands in the fall preceding. “This natural destruction is, without 
doubt, a great help in reducing the numbers of the pest in western New 
York. While the eggs need moisture for their development, excessively 
wet surroundings are unfavorable, for under such conditions they become 
moldy and spoil tho they may retain their normal shape. Ina dry environ- 
ment, the egg covering will shrivel and the egg will contract until it might 
be mistaken for a particle of the dirt on which it rests. When moisture is 
added, however, it will again swell to normal size. Bland and Binney 
(1873) describe experiments in which eggs of A. agrestis were dried many 
times in a desiccator, in some cases being kept in this condition for several 
years; when these eggs were again placed in normal moist surroundings, 
they assumed their usual shape and hatched. Since the development of 
the embryo in the egg is easily observed, much study has been given to 
this part of the life cycle by Mark (1881), Kofoid (1895),and Byrnes (1899). 
The young slug 
Newly hatched specimens of Agriolimax agrestis differ but little in their 
habits from the full-grown slugs. Because of the limited food supply 
in proportion to the large number of slugs hatching from a single egg mass, 
these slugs appear gregarious. As they become older and more hardy, 
they migrate from the original center and spread out in search of other 
food. Cooke (1895) reports that on hatching they go into the ground for 
four or five days before feeding. The writer had noted that green food in 
cages did not show strong evidence of feeding for several days after the 
slugs hatched, but he had attributed this to the small size of the radula, 
or rasping organ, at this time. 
The young slug often secretes its slime in such large quantities that it is 
able to descend from plants to the ground on a thread of this material. 
Taylor (1907) states that this slime thread is the same as the trail left by 
the slug wherever it crawls, except that it is freed from contact with the 
