It was to be my duty to amass specimens especially of insects, 

 to arrange some of them in sj^stematic series, others in faimal series 

 and still others as types of groups for the use of teachers in the 

 public schools. He advised me to take every opportunity to ac- 

 quire a knowledge of the range of variation in species, and to try 

 to discover the reasons for the plan of structure of the articulate 

 type. His frequent visits to my room in the museum, gave me an 

 opportunity to become better acquainted with his great mental 

 grasp, and almost intuitional perception of the fundamental prin- 

 ciples of structure in a group. The most elaborate outer covering 

 of details failed to hide from his keen vision the basis of construc- 

 tion which rested beneath. His versatility, enthusiasm, and desire 

 for more specimens of natural history appeared to have no bounds. 

 No price nor trouble seemed too great to expend when coveted col- 

 lections were needed to fill out his plans for a universal museum 

 of representative species. 



The American continent had for him a peculiar charm. He 

 loved its mountains, plains, and waters, and every object connect- 

 ed with them, whether living or fossil. Every pebble and bit of 

 shale had a story for him; the simplest insect, as well as the most 

 complicated animal, alike spoke to him of an intelligent plan in 

 creation, of which he rejoiced to be the interpreter. Every region 

 of North America was expected to contribute its representative 

 species for study and exhibition in his museum. Consequently, 

 each assistant was encouraged to make frequent excursions to the 

 most promising localities, to secure the forms belonging strictly 

 thereto. One of these short trips resulted in a very pleasurable 

 surprise to me, which perhaps you will pardon me for reciting. 

 The salt-marshes of Eastern Massachusetts are well provided with 

 forms of insect life. In midsummer, when the tides fail to cover 

 these wide areas of low surface, multitudes of small, rather flat in- 

 sects, belonging to the Hemipterous genus Salda, inhabit the wet 

 mud and damp sand there. They constitute separate species of 

 three or four sizes and of different colors. The largest is of a deep 

 uniform black, a smaller size is tan-brown, a third is almost uniform 

 sand yellow, and a fourth is black, marked with small white spots. 

 On Cape Cod there is a fifth species which is almost all white on 



