62 THE ENTOMOLOGIST. 



species surpassing wild examples in the matter of wing expansion. 

 On the other hand, careless breeders — those for instance who 

 fail to supply their charges with a liberal quantity of food or with 

 a suitable pabulum — rear nothing but under-sized specimens. 

 So we see that it is quite possible to increase or decrease the 

 normal size of a species, even in one generation. To what extent 

 it is possible to increase the size of any given species has not yet 

 been demonstrated, but it is easy to foresee that the limit in the 

 opposite direction would be speedily reached. Probably semi- 

 starved individuals would be incapable of producing fertile 

 offspring, and so such a " breed " would die out with the second 

 generation. 



Experiments of this nature do not, however, come within the 

 scope of Mr. Galton's proposed investigation. He only desires to 

 set apart the smallest individuals of a brood on the one hand, 

 and the larger on the other, reserving a selection of the remainder 

 for the medial race. Each race is to be kept apart, and the 

 parents of each of several successive generations to be respectively 

 the smallest of under average-sized race, the largest of above 

 average-sized race, and the medium-sized individuals of the 

 medial race. 



In conducting such a course of breeding the larvae should, 

 properly, be subjected to exactly the same external influences, 

 and supplied not only with the same kind of food, but spraj's or 

 branches from the same plant. If this is not done all would 

 not be on equal terms, and descendants of the originally 

 smaller individuals might, by being placed in a more favour- 

 able situation and fed on a more nourishing food, attain, 

 or even excel, the size of the descendants of the larger 

 original pairs. 



Anyone who may feel disposed to aid in these investigations, 

 upon which questions of considerable scientific value depend, will 

 do well to communicate with Mr. Francis Galton, 42, Portland 

 Gate, London, S.W. ; or Mr. F. Merrifield, 24, Vernon Terrace, 

 Brighton. R. S. 



