410 The American Naturalist. [May, 



Indeed there are many facts that he either ignores or of which he is 

 unaware that are far from lending support to his interpretation of the 

 lines. Some of these I have pointed out elsewhere 2 when considering 

 the subject of the diplopod segmentation. Mr. Cook seems unfor- 

 tunate in thinking of the greatly overgrown dorsal plate in the diplo- 

 pod ring as the segment or somite, and in drawing his comparison from 

 the geophilids. Had he examined the conditions occuring in the 

 pauropods and those in Lithobius, Scutigera and scolopendrids, and 

 taken into account some of the ontogenetic facts known regarding 

 diplopods, he doubtless would have plainly seen indications of alter- 

 nate plates (not segments) having disappeared and of the remaining 

 plates over-growing the segments behind them, so as to give rise to the 

 anomalous double segments. There would then have been no reason 

 for bringing forward the most decidedly unprogressive supposition, 

 namely, that the double or apparently double condition of the diplopod 

 segment is a condition mi generis unexplainable upon general morpho- 

 logical principles. 



With reference to his supposition that alternate leg pairs have dis- 

 appeared even in the geophilids, the case that he has in mind in 

 mentioning the Chilopoda, I must say there is no evidence whatever. 

 To adduce the geophilid condition as evidence is to adduce the thing 

 to be explained. Therefore, 1 at least am not able to agree with him 

 in saying that this view is no more fantastic than the old fusion idea 

 of Newport, since the latter has some real ground and many favorable 

 appearances in its support, even though it be incorrect. 



— F. C. Kenyon. 



The Sight of Insects. — M. Felix Plateau has been conducting 

 a series of experiments to settle the question as to whether an insect 

 in flight will go through a net the size of whose meshes would offer no 

 obstruction to the passage of the insect. The question has a bearing 

 upon the difference of vision of Insects and Vertebrates. Mr. Plateau's 

 recent experiments would seem to confirm the statement made by him 

 in 1889 that the vision of insects is obscure as to form, and is adapted 

 more to the perception of movements. 



The data upon which the paper is based were acquired by means of 

 ingeniously contrived nettings of various shapes, with meshes 26 to 27 

 millimeters and 1 to 2 centimeters in size. These nets were placed 

 over attractive lures, such as flowers that insects frequent and in other 

 cases decaying animal matter. The results of the author's observations 

 are given in the following conclusions : 



2 The morphology and classification of the Pauropoda, Tufts College 



