OF WASHINGTON. 387 



The paper was discussed at length by Messrs. Cockerell, How 

 ard, Ashmead, Gill, Sanderson, and Schwarz. Mr. Cockerell 

 said that the paper was too general and could hardly be criticised 

 in general terms. Only two specific instances were mentioned 

 by the author. He expressed his belief in the value of the char 

 acters of the scale and also in the value of the characters to be 

 derived from the measurements of the relative length of the an- 

 tennal joints. He admitted the variability described by Mr. 

 Marlatt, but insisted that by the careful study of extensive mate 

 rial we may reach the specific limitations of this variability and 

 that the characters will thus be found to be of use. He spoke of 

 forms which while practically impossible to distinguish morpho 

 logically, still had distinct geographical range and distinct food 

 plants. He had made distinct species or varieties of such forms 

 and believed himself justified in so doing. He referred to the 

 fact that Aspidiotus perniciosus does not occur upon orange 

 in California, while an undistinguishable form has been received 

 from Japan occurring upon orange. He had made a variety of 

 this Japanese form, although no distinct characters in the insect 

 itself could be found. 



Mr. Howard said that he could not help believing that this last 

 mentioned Japanese form was distinct from the true Aspidiptus 

 perniciosus. Referring to Mr. King's variety fulvus of 

 Chionaspis furfurus, he said that type specimens had been sent 

 to him by Mr. King before the variety name had been given, and 

 that he had urged Mr. King not to make a new variety for 

 it ; he thought it entirely unnecessary, and, in fact, misleading, 

 thus indicating his general agreement with the points laid 

 down by Mr. Marlatt, with whom he said he agreed almost 

 perfectly. 



Mr. Ashmead said that he believed that the scale was of great 

 importance in classification ; that it frequently not only indicated 

 specific differences, but generic differences, and that differences 

 in the scale must represent differences in structural characters of 

 the insect. These characters may be minute and difficult to de 

 tect, such as the secretory pores. 



Dr. Gill, apropos to Mr. Ashmead's remarks, referred to the 

 general subject of secretions and excretions of animals as expres 

 sive of morphological structures, and spoke particularly of the 

 specific characters of the dejecta of mammalia. 



