194 
THE entomologist’s RECORD. 
with notes on the seasons in each locality, was doubtless of 
"reat importance and aid in illustrating the paper. By this 
means alone can the effects of the seasons and climate in 
producing variation on any form be fully worked out. The 
experiments of Mr. Merrifield and others have shown that 
great variation can be produced by artificial methods, but the 
results in all cases cannot be accepted as an exposition of the 
natural causes of variation. They, however, will be the 
means of suggesting other and better methods, and lead to 
better results when studying the subject from a purely natural 
aspect. 
The theory of the progressive development of bands on the 
wings of lepidoptera caused by the union or coalescence of 
lines in certain seasons and under certain conditions, is un- 
questionably based on a line of reasoning that will ultimately 
lead to the perfect elucidation of this form of variation, by it, 
the genealogy of many so-called species and varieties will be 
traced to this true source of origin. The variation of British 
lepidoptera affords the best of all opportunities for the full 
investigation of the subject. The many able and earnest 
workers resident throughout the country, and the Continental 
interchange of specimens, notes of experiments and discoveries, 
will always enable British entomologists to lead the way in the 
science of variation. The resolution recently adopted by some 
of the London societies to devote certain evenings to special 
groups or subjects is another step in the right direction towards 
dispelling any doubts, and adding new facts to the subject 
selected. 
With reference to Mr. Tutt’s remarks on reversion and the 
progressive development of Lepidoptera from dark to light 
forms, or vice versa, I would remark that after much close 
observation on the subject in New Zealand, I unhesitatingly 
agree with Mr. Tutt in believing the former to be the right 
view of the two. In all cases where dark or melanic forms 
occur in our climate, they can readily be shown to be partial or 
perfect instances of atavism produced in certain districts in- 
variably more humid than the localities where the lighter forms 
occur, and more typical of their ancestors formerly existing in 
the ancient and more humid climate of the Islands. The New 
Zealand climate has undergone considerable modification since 
the advent of European settlement, and its effects are working 
rapid and ruinous changes in the flora and fauna of the 
country. The changes in the environment and economy of 
