Some time ago, Prof. Gillette sent me a few specimens of an Aspidiotus found on plum at Cañon City, Colorado 31st Aug., 1894. They occurred on the fruit itself. He had previously sent the species to Mr. L. O. Howard, who had written that it was apparently new. The material sent was not altogether satisfactory, owing to the fact that the insect occurs solitarily on the fruits, and has to be collected by slicing off bits of the skin. Consequently it is inconvenient to obtain it in quantity, and not very easy to nicely preserve those obtained, However, the discovery of a new Aspidiotus on plums in the United States was a matter of importance, and deserved the most careful consideration.