8 THE NAUTILUS. 



shells have often a somewhat corroded surface, the bands becoming- 

 indistinct or absent. When the conditions are unfavorable, either cold 

 or dry, the snails take refuge in the hollows of the trees or under 

 leaves accumulated in the forks, or elsewhere, or under sacks at the 

 base of the trees when these are provided. It thus becomes an easy- 

 matter to transfer them from tree to tree. A few snails placed by- 

 Mr. Wade Harrison in one of his trees in March, increased in such 

 numbers as to free the tree of sooty mould by mid-summer of the same 

 year. The snails are known to range with some variation from the 

 mouth of the St. John's river on the north, to the Caloosahatchie river 

 on the south. The species is probably native to Florida, as speci- 

 mens in small numbers were observed about the hummocks and else- 

 where as long as fifty years ago. Its habit of feeding on the sooty 

 mould of the orange, however, was not known until within the past two 

 years. 



In view of the fondness of the snails for the injurious sooty mould 

 fungus, it becomes of first importance to observe their treatment of 

 the beneficial fungi. Among the fungi parasitic on orange insects 

 there are four species of inestimable value to orange growers. These 

 are the brown fungus well known as an effective parasite on the 

 white fly larvas ; the red-pink fungus also parasitic on the white fly ; 

 the red fungus, and the gray-headed fungus, both parasitic on the 

 common scales. The brown fungus so effective in control of the white 

 fly, as is well-known, throws out spreading hypha? for some distance 

 around the body of the dead leaves. It seems that the snails occasion, 

 ally feed to a limited extent on these spreading hyphae, but evidently 

 not enough to interfere with the spread of the fungus, since this fungus 

 is doing particularly effective work in the groves in the Manatee region 

 where the snails occur ; the red-pink fungus is also abundant in the 

 groves where the snails occur and is untouched by them. The snails 

 have not been observed to feed on either the red or the gray fungi 

 parasitic on the common orange scales, and it is probable that they 

 have no taste for these parasitic fungi. Colonies of the snails are 

 being started in parts of the State where the white fly injury is severe 

 and where conditions seem favorable for the growth of the snail. It 

 is desirable that close attention be given to the habits of the snail, as 

 well as to means of protecting colonies against unfavorable conditions. 

 A few sacks thrown around the tree seems to afford a needed protec- 

 tion against unusual cold. It is probable that sprays can not be used 



