129 



better liglit and prove interesting to both the entomologist and con- 

 chologist. 



On the same bench in tlie insectary where the observations were 

 made were growing probably twelve to fifteen wild and cultivated 

 plants, Dock being one of the former. In the course of time this last 

 became thickly populated with Aphides, comprising for the most part 

 apterous females and their progeny. My attention a\ as first drawn to 

 the matter by the fact that where these slugs were on the leaves there 

 were great numbers of the Aphis in front of them, but very few in 

 their rear. On placing an Aphis within the reach of one, it grasped it 

 in its jaws and devoured it. Another aud still another followed. Then 

 after patient watching I saw it capture others without assistance. 



At the other end of this bench, perhaps four yards distant, was grow- 

 ing probably a square yard of wheat, and adjoining this a similar plat 

 of lettuce, which is given by Mr. Binney as one of its food-plants. The 

 mollusks had been observed repeatedly feeding on the lettuce, of which, 

 as the i^lants were large, there was always more than an abundance. 

 But they also climbed the leaves and stems of the wheat to the height 

 of 8 or 10 inches, and crawling along the larger leaves cleared them 

 almost completely of the Aphidids, which in this case was Fhorodon ma- 

 lialeb Fonsc. So, then, it would seem that this food was taken of their 

 own volition, and, indeed, they made considerable effort to get it, as 

 they did not, so far as I could see, attack the wheat. The slugs were 

 observed to feed as above stated only during the night and on after- 

 noons of very dark cloudy days. 



The market gardener or florist, whose interest is wholly in his 

 plants, would, as a matter of course, be quick to observe any injury to 

 them. The entomologist, whose eyes aud mind have had a different 

 training, would be much more likely to notice such variations in food 

 habits. Therefore it seems to me at least possible for the much abused 

 slug to, in part at least, repay for the injury caused by its plant-feed- 

 ing proclivities by destoying other enemies of that i)lant. The lettuce 

 was also infested by another si^ecies of Ai^his, and, had the slugs con- 

 fined their attention to them, it might have been, to some extent, an act 

 of self-preservation, on the score of protecting its food-plant. But they 

 voluntarily went to the wheat, upon which they did not subsist, nor 

 was it likely that the juices of the Aphids which they ate savored of 

 lettuce. It is entirely beyond my desire to magnify either the impor 

 taiice of these observations or the i^ossible usefulness of this Limax. 

 The desire to be just, without being unjustly just, has prompted the 

 presentation of this whole matter. 



Mr. Eiley thought it an illustration of the ease with which some ani- 

 mals may pass from food comprising soft plants to the soft, juicy bodies 

 of some insects. 



Mr. Bethune had observed repeatedly slugs feeding on the mixture 

 of beer and sugar used in sugaring for moths. 



