In May many leaves of the pear tree were observed to be covered with dark-brown blotches somewhat like a fungoid growth, but upon examination by Mr. Taylor, microscopist of the Department, these blotches were found to be inhabited by small mites almost invisible to the naked eye. These mites appear to run all over the leaves, but especially to burrow in the brown patches, which appear to be entirely eaten out by them. Their bodies are long, cylindrical, yellowish-white, with only two pairs of legs, placed very far forward near the head, and they move with considerable agility. They are also marked with a multitude of rings, and have two long hairs or bristles and two shorter ones on the end of the abdomen. There is a somewhat similar mite mentioned by Packard as the Typhlodromus pyri, of Scheuten, which is said to live under the epidermis of pear leaves in Europe, but no mention is made of the brown blotches on the leaf, apparently formed by the mite. In his figure also the head is much more obtuse than those examined in the Department. A thorough drenching with whale-oil soap-suds would doubtless destroy many of them, as their bodies appear to be very soft.

All infested leaves, likewise, should be immediately removed and burnt as soon as discovered".

I see by the Scientific American of recent date that Prof. Barnard, of Cornell University, claims to have been the first to discover the mite, and read a paper on the subject before the Scientific Association at Saratoga last August. You will perceive by the dates given in both instances that my discovery was prior to either by some years.