This expedition, the first official one of the Academy, included J. E. Ives, Roberts LeBoutillier, Witmer Stone and Frank C. Baker in the party. Arriving on the 22nd of February, they covered the territory of the northwestern part of Yucatan and the Mexican highlands in the vicinity of Orizaba. Natural history specimens were gathered and photographic records of the ecological conditions and the contours of the country through which they travelled, were taken. The short time spent in the field ended in June of 1890, but the resultant additions to the Academy's museum collections were great. Accounts of the results appeared in the Proceedings of the Academy for 1890. Two documents from the U. S. State Department are retained here, documents which paved the way for the party.