252 
MOTHS AND BUTTERFLIES. 
not alike; the males and females differ, and interesting varieties are 
occasionally taken. Then he wishes to show both the upper and the 
under side of the species, and at length he falls in with some other 
beginner who wants to exchange, and he then thinks of the many 
good specimens he might have collected. His ideas enlarge with his 
collections; his collector friends and his need for good specimens for 
exchange constantly increase, and the truth finally dawns on him 
that large numbers of first-class specimens are not only a conven¬ 
ience but almost a necessity if he desires to increase his own col¬ 
lection beyond the limits of those which he can himself capture. 
Alfred Russell Wallace once told me that one of the hardest les¬ 
sons he had to learn in his many years of collecting in tropical coun¬ 
tries was that it is hardly possible to get too many specimens of a 
Timetes petreus. 
good species of bird, shell, beetle or butterfly, and that on several 
occasions he had retraced his journey hundreds of miles to little 
known islands to procure additional specimens of species he had pre¬ 
viously collected, at the time supposing lie had taken all he would 
ever need. 
One person can cover but a small portion of the earth’s surface 
during a lifetime, and one can expect to collect personally but a 
