: Aii Instance of Mutation? 153 



Much stress is laid upon the presence of a .slight deposil 

 of mealy powder beneath the bodies of certain species of 

 Lecanium; but the secretion of wax— in greater or less 

 profusion — may be said to be common to the whole family 

 of Coccidae. In some it is profuse, in others it is small in 

 quantity and restricted to definite areas of the body. It 

 is not the secretion of meal that distinguishes the genus 

 Pulvinaria, but the construction of a definite ovisac. I 

 may remark, however, that I do not attach any great 

 value to generic distinctions, but regard them greatly as a 

 matter of convenience. 



1 am quoted as writing (in the " Coccidae of Ceylon ") 

 that " in all purely structural characters there is nothing 

 to distinguish the members of this genus [Pulvinaria) from 

 those of Lecanium; so much so that until the period of 

 ovi position it would be impossible to determine whether 

 an individual should be placed in one genus or the other." 

 This statement is applicable only to the genera, and must 

 not be held to imply that two known species could not be 

 distinguished at an earlier stage. 



In conclusion. I see no more justification for regarding 

 Lecanium viride and its allies as having been directly 

 derived from Pulvinaria j>xi<lii than for assuming a similar 

 relationship between L. hesperidum and P. floccifera, or 

 many other pairs that might be mentioned. By a skilful 

 manipulation of figures and charts it might be made to 

 appear that all the genera and species of the Lecaniinae 

 (or of any of the other subfamilies) were in an active state 

 of flux. There is no doubt that the genera Pulvinaria 

 and Lecanium are very closely allied, but their boundaries 

 are quite well defined. 



After the kind acknowledgment of encouragement, in 

 the final paragraph of Mr. Kannan's paper, I feel that the 

 above remarks have placed me in a rather invidious 

 position, and may seem to savour more of discourage- 

 ment than the reverse. Rut I really consider that the 

 author is to be congratulated upon having brought 

 together so many interesting and valuable observations, 

 and having drawn attention to the close inter-relationship 

 that undoubtedly exists between many species and genera 

 of Coccidae. Though i have been unable to agree with all 

 his conclusions, I feel that a broader view of the subject — 

 such as he has here attempted — will be greatly to our 

 advantage, and I trust that Mr. Kannan will continue 



