An Instance of Mutation.' 



151 



evidence— in support of his theory; but much of this is 

 open to question. The first four clauses may be accepted 



* 220 



A comparison of various organs of Lecanium viride and Pulv. 

 psidii. (The figures have been drawn to scale, with the aid of a 

 camera lucida; each pair being amplified to the extent that best 

 shows their relative proportions.) 



Lecanium viride. 



I, antenna, X 220. 



3, mid leg, X 80. 



5, posterior spiracle, X 280. 



7, marginal hair, 450. 



9, anal operculum, > 135, 



Pulvinaria psidii. 



2, antenna, X 220, 

 4, mid leg, X 80. 

 6, posterior spiracle, X 280. 

 8, marginal hair, X 450. 

 10, anal operculum, X 135. 



almost without comment, except that I may point out 

 that the third does not necessarily follow upon the second, 



