278 CORRESPONDENCE. 



specific form of tlie vine phylloxera ; for it has characteristics that 

 distinguish it from all other shapes hitherto known. ... Its size is 

 ^4_2_. of a millimeter in length by 16 in breadth. It has long and 

 slender antennae, a fusiform terminal article attenuated at its base 

 and a well-developed rostrum, the point of which advances down to 

 the middle of the abdomen. . . . The individual I have been de- 

 scribing is the only one of its generation I have yet obtained ; I 

 cannot therefore give any information as to its habits ; but among the 

 eggs that were on the same vine shoot there are several containing a 

 well-developed embryo, which is recognizable by its two red ocular 

 points, visible through the teguments of the egg. I hope, therefore, 

 to be able to make some further observations." 



Microscopy at the American Association. — This, which has 

 hitherto been feebly developed, bids fair to become a prominent part 

 of the Association in future years. This Section, which was formed at 

 the last meeting, is now undergoing favourable development. The 

 club which has been started for the purpose, now invites all persons 

 interested in the microscope, and desirous of joining such an organiza- 

 tion as is now proposed, to be present and co-operate, whether at 

 present members of the Association or not, and they are requested 

 to bring to the meeting original paj^ers of scientific interest upon 

 subjects connected with the microscope and its work, and also to 

 bring instruments, accessories, and objects, especially those illus- 

 trating new or unfamiliar inventions, contrivances, and discoveries. 

 It is hoped that the jiarticipation of microscopists in . this movement 

 will be prompt and cordial. 



COKEESPONDENCE. 



To the Editor of the ' Monthly Microscopical Journal.' 



HoBART College, Geneva, N.Y., April 10, 1876. 



Sru, — Mr. Hickie in his reply to Dr. Woodward, in the March 

 number of the ' Monthly Microscopical Journal,' makes two distinct 

 issues : First, Frustulia Saxonica has true longitudinal lines ; and 

 second, Frustulia Saxonica is not Navicula crassinervis. I do not 

 intend to discuss the first ; Dr. Woodward and Mr. Hickie must settle 

 that for themselves ; but the second statement is, in my opinion, 

 erroneous ; and I am sure Mr. Hickie, when he has made more com- 

 plete study of the Diatomaceae, especially as to what is to be con- 

 sidered of value in establishing species and genera, will agree with 

 me. Let him read Mr. Kitton's article on " the publication of new 

 Genera and Species from insufficient material." * 



Mr. Hickie sums up the evidence in favour of his assertion 



* ' Journal Quekett Microscopical Club,' Feb. 1 867, and published in ' Q. M. J.,' 

 vol. vii., N. S. 



