Prof. Riley exhibited a specimen of Doryphora 10-lineata, that was so completely cov ered with a mite parasite belonging to the Gam asidse, and apparently the Gamasus coleopteratorurr, that the point of a needle could not be placed on any part of the beetle's body without touching one of the parasites. He estimated that there were over eight hundred of the mites, and they had killed their victim. Aside from the toad and other reptiles, the crow, rose-breasted gros-beck and domestic fowls among birds, which prey on the potato pest, he had, in his Reports, figured or described no less than twenty-three insect enemies that attack and kill it. Only one of these is a true parasite, and the mite exhibited made the second, or just two dozen insect enemies in all.- Proceedings of the St. Louis Academy of Science, June 19th.