522 



MERISTIC VARIATION. 



[part I. 



must, I think, be judged to be a possible account, and in this case R 

 and L' are, as regards symmetry, in Position P. It is of course possible 

 that Ls and R are really the extra pair in Position A, but the presump- 

 tion is rather the other way '. Specimen in Hope Collection at Oxford. 



(2) Cases of double extra antennce, Symmetry unknown. 



802. In none of the following can any confident statement be made 

 as to the symmetrical relations of the parts. Several of the 

 cases I have myself seen, but I noticed no clear indications as 

 to their symmetry. A good many of them however were ex- 

 amined before I was fully alive to the importance of these matters 

 in the case of filamentous antennas, and perhaps if they were 

 studied with proper regard to the question of symmetry more 

 might be made of them. Many cases that follow are mutilated 

 or partly amorphous, and of almost all the descriptions are very 

 imperfect. For our purpose some value attaches to these records 

 as evidence of the distribution of such abnormalities, and to 

 any person who may hereafter pursue the subject a fairly com- 

 plete list of the references may be of use. To this therefore I 

 shall confine myself; for on reviewing the abstracts that I have 

 made of these examples it is clear that they only give the results 

 of superficial examination. 



Speaking generally, in these cases, from some one joint of an 

 antenna there arises either a pair of extra antennas compounded 

 for a greater or less extent of their proximal parts, or two extra 

 antenna? distinct from their point of origin. 



The letters R and L indicate the side affected, and the number 

 following is approximately that of the joint from which the extra 

 parts spring. In the greater number of sound cases the three 

 branches lie in or nearly in a horizontal plane and are, I anticipate, 

 in Positions A or P. 



Cases which seem from the indications to conform to the 



Scheme are marked ||. Mutilated or partially amorphous cases are 



marked %. 



R3 Mocquerys, Coleapteres anormaux, 1880, 

 p. 5, Jig. 



Blaps attenuata (Het.) 



This is perhaps too strongly put. 

 Description aud figure incorrect. 



Apical joint of extra branch is bifid. 



