AbstractIps calligraphus (Germar) is distributed continentally throughout North America, including Guatemala and British Honduras. It has been collected on only rare occasions in California, primarily in the central Sierra Nevada Mountains. Four generations were observed during 1961 and 1962, and average summer development required about 40 days. All stages except the egg were observed in the winter. The unique gallery system exhibits four to six egg galleries, which range in length from 25.4 to 38.1 cm, and radiate characteristically from a large, irregular, nuptial chamber excavated by the male. At Grass Valley, Cal., this bark beetle was observed breeding predominantly in the thick-barked portions of the lower bole. Its galleries are often intermixed with those of Dendroctonus brevicomis LeConte, I. confusus LeConte, I. latidens LeConte, and Melanophila californica Van Dyke in ponderosa pine. I. confusus was the most abundant species of Ips in all localities where I. calligraphus was found.
