88 STATE HORTICULTURAL SOCIETY. 



Along with injurious mites might be mentioned those that work in cheese, 

 flour, milk, sugar, and other products, but space will not permit. 



It is more agreeable to learn of a friend than an enemy, and I will speak of 

 a few beneficial species that deserve attention here. 



Most beneficial mites are, as is the case with insects, those that in their strug- 

 gle for existence, prey upon and destroy others of their kind. 



Fig. 6 represents one of the mites belonging to the family Gamasidce, which 

 is very common upon many of our large beetles that infest moist places, whether 

 it be in earth, filth, or decaying wood. These mites are brown in color, and 



Fig. 6. 



have a hard, chitenous shell. They have no eyes, are possessed with strong 

 chelate, or shear-like mandibles, Fig. 6, and the front pair of legs have the 

 terminal joints turning down, and seem to be used more as feelers than as 

 feet. In the species represented in the cut, the front pair of feet terminate in 

 sensitive hairs instead of claws. 



To this same family belong Uropoda Americana, which Kiley describes as in- 

 festing the potato beetle, and several species that infest birds, bats, and do- 

 mestic fowls. 



While speaking of mites infesting insects I will mention a small, bright red 

 mite in the larval or six-legged state which I have found preying quite exten- 

 sively upon the plant lice this summer. I have taken them upon the cherry, 

 milkweed, and willow lice. I examined one milkweed which had hundreds of 

 plant lice, and hardly less than half of them were carrying about upon their 

 ventral surfaces one of these little bright red mites which, to all appearances, 

 were sapping the life-blood of their defenseless victims. 



In the genus Tyroglyphus, Tyroglyphus phylloxera, is mentioned by Riley 

 as being destructive to the Phylloxera? of the grape vine. 



Tyroglyphus malus, (Riley), is very useful to fruit growers, as it destroys the 

 eggs of the apple-tree bark louse iri large numbers. I had no trouble to find 

 plenty of these mites infesting the bark louse scales in the orchard of the 

 Michigan Agricultural College last spring. 



