Vlll LIST OF ILLUSTRATIONS. 



FIGURES IN THE TEXT. 



Page 1. Diagram of aplanatic system. 

 ,, 4. Abbe's test for aplanatism. 

 „ 5. Cheshire's apertometer. 

 ,. L'l\ Diagram of test-plate. 

 „ 23. Light-intensity diagrams. 

 2 I 



25. 



96. Antennae of Diptera. 



106. Pseudofeltria scovrjieldi, n. sp. 



107. Mideopsis erassipes, n. sp. 



118. Small glass tank. 



119. ,, ,, „ (another form). 

 138. The Rousselet Compressorium. 

 142. Diagrams of spherical aberration. 



1 13. Diagram illustrating the sine law. 

 1 \ R 



***»• 11 11 11 



146. Diagrams of un-corrected and over-corrected lenses. 



117. ,, achromatic lenses. 



148. Diagram of photographic objective. 



150. „ apochromatic lens. 



167. Filaments from foot of house-fly. 



160. Modified Rousselet Live-box. 



173. Diagram illustrating doubling of lines in Abbe experiment. 



174 



■*■ • 3 ' 5? >J 11 11 11 11 



223. Discoi'hina parisiensis, plastogamic, 



234. Diagram of genitalia as usually found in Diptera. 



2".i2. Stops used for producing stereo-photo-micrographs. 



328. The Coon Finder. 



360. Eggs of water-mites. 



366. Nymph of Eulais. 



376. Diagrams of stereoscopic vision, etc. 



429. Stops used in stereo-photo-micrography. 



430. Double image produced by suitable stop. 



441. Diagrams showing effect of iris upon image. 

 449 



