( Ixx ) 



understood, the part which the study of insects will have 

 played in arriving at that state of knowledge should certainly 

 be not inconsiderable. 



The investigation instituted by Mr. Francis Galton with a 

 view to determine the percentage of hereditary transmission 

 to successive offspring by different generations of predecessors, 

 whatever may be the final results, whether negative or 

 positive, of Mr. Merrifield's experiments, is an acknowledg- 

 ment of the value for such purposes of the means which 

 entomologists have at hand for following the life-history of 

 very numerous generations within a comparatively short 

 space of time, whereas in other branches of Zoology such an 

 investigation might be almost hopelessly prolonged, costly, 

 and inconvenient. 



Although the value of Entomology as a means of throwing 

 light upon many interesting problems now occupying a fore- 

 most place in scientific investigation must be generally 

 acknowledged, I will add one further illustration to my argu- 

 ment. The majority of known insects being phytophaigous, 

 their occurrence in or absence from certain defined areas of 

 the globe should frequently enable us to check the conclusions 

 of botanists and zoologists with regard to the progress of 

 geographical distribution, for whereas the seeds of plants are 

 easily conveyed by rivers and marine currents, by hurricanes, 

 or by the instrumentality of birds and animals, the insects which 

 feed upon those plants being often of very delicate structure 

 and of inactive habits, are less easily transferred from place 

 to place, and by no means generally accompany their native 

 food-plants in the march of natural or artificial acclimatisa- 

 tion. It is remarkable how many insects continue to be 

 exceedingly local in their occurrence, although precisely 

 similar conditions of food and climate may prevail at no great 

 distance from the limited districts they are known to frequent. 

 On the other hand, when we find local genera, and perhaps 

 even species, occurring in West Africa and on the opposite 

 coast of South America, those who believe in the submergence 

 of Atlantis may perhaps claim that such species must have 

 been distributed to east and west from their original habitat 

 on an interjacent continent. To estimate the possible value 



