( 149 ) 



VIII. Some Remarks on Mr. Kunhi Kannan's Paper, " An 

 Instance of Mutation." By E. Ernest Green, F.Z.S. 



[Read March 6th, 1918.] 



The author records some extremely interesting observations 

 on a marked degeneration (that has appeared within quite 

 recent years) in the antennae of two nearly related Cot '.cidae - 

 Lecanium (Coccus) viride&nd Pulvinaria psidii. 



In the year 1882 a green scale-insect attracted attention 

 in Ceylon as a serious pest of the coii'ee plant, though it 

 was not until 1886 that it was recognised and described 

 as a new species — under the name of Lecanium viride. 

 The same species was found to be infesting the coffee 

 plantations of Southern India a lew years after its first 

 appearance in Ceylon. It does not appear to have been 

 in it iced in the Mysore district until 1912, at which time 

 the insect is said to have been quite typical in regard to 

 the structure of the antennae. Mr. Kannan reproduces 

 a photograph of "one. of the first specimens sent in for 

 identification at the outbreak of the pest," which exhibits 

 sc\ en-jointed antennae. Yet, by the following year (1913), 

 the Mysore examples of the insect — though otherwise 

 typical of the species — were found to have undergone a 

 remarkable degeneration which took the form of a reduc- 

 tion of the number of antennal joints to 5, 4, and 3, instead 

 of the normal number of 7. This (as may be gathered 

 from the author's figures) w^as effected hy a suppression 

 of intermediate divisions until — in the final stage — there 

 • remained only the normal 1st and 2nd joints, with a long 

 compound segment consisting of the other 5 joints with 

 little or no trace of the former divisions. It is now said 

 to be difficult to find a single example with antennae 

 showing more than three visible segments. From a 

 consideration of these facts the author arrives at the 

 conclusion that a new species has been suddenly evoked. 

 and he proceeds to describe it — under a new name— as 

 Coccus colemani. 



1 have had no opportunity of examining examples of 

 this insect, hut presuming that it has been correctly identi- 

 fied and that it is really a sudden mutation from the original 

 Lecanium viride, it still seems questionable if there is 



TRANS. ENT. SOC. LOND. 1918.— PARTS I, II. (DEC.) 



