76 SUMMARY OF CURRENT RESEA.RCHES RELATING TO 



are emphasized. He weiglis the arguments in favour of Japijx and 

 Campodea being degenerate rather than primitive, but firmly maintains the 

 latter, regarding them as approximately ancestral forms of the winged insects. 

 Anatomy of Machilis.*— (Continuing his researches on prinaitive 

 insects. Prof. B. Grassi describes in detail the anatomy of two species of 

 MachiUs, which he compares throughout with Jcqnjx and Campodea. From 

 the tracheal system especially, he is inclined to regard Machilis as the form 

 nearest to the primitive insect type. The structure of the two species is 

 rewarded as sufficiently distinct to warrant the erection of a special family, 

 MacMUdx. The habit of the Orthoptera begins to be accentuated in 

 Machilis, and more so in Lejnsma. Grassi notes the return to the old 

 system, to which his researches have done much to supply a new morpho- 

 logical basis. 



Structure and Metamorphosis of the Aspidiotus of the Rose-laurel. f 

 — The presence of this Coccidian is revealed by numerous whitish spots on 

 the under side of the leaves of the rose-laurel. M. Lemoine finds that the 

 female consif^ts of an oval sac filled with eggs, with neither antennae, eyes, 

 nor legs. The adult male possesses long antennae, four large eyes, two 

 wings, balancers, and well-developed legs. 'I'he author has studied the 

 whole series of changes passed through by male and female during develop- 

 ment. Both sexes are similar up the third age, i.e. after the second 

 ecdysis ; the female stops here ; but the male goes on through a fourth 

 ecdysis, when it becomes a nymph, and then after a fifth is the perfect 

 insect. The result of these researches does away with the supposed ex- 

 ceptional characters of the development of this insect. 



0. Myriopoda. 



Light-perception by Myriopods.:}: — Fourteen years ago Pouchet showed 

 that muscid larvte without eyes were still sensitive to light, and Graber has 

 recently in some striking experiments extended the same conclusion. 

 Prof. F. Plateau gives a careful historical survey of what is known in 

 regard to light-sensitiveness among Invertebrates, and reports the result 

 of his own recent researches on blind myriopods. 



His method of experiment was manifold. That of Pouchet, that of 

 Graber, and two other modifications were employed in order to determine 

 whether the blind myriopods were able to perceive light, while in another 

 series M. Plateau sought to ascertain the rapidity of perception. 



His chief results are summed uj) as follows : — The blind chilopod 

 myriopods perceive the daylight, and are able to choose between it and 

 darkness ; in the chilopod myriopods provided with eyes, and in those 

 without these organs, a considerable time must elapse before the animals 

 perceive that they have passed from relative or complete obscurity to day- 

 light ; the length of this latent period is not greater in the blind myriopods 

 than in those with eyes ; owing to the general slowness of perception, blind 

 myriopods, although sensible of the light, may cross a dark space of small 

 extent without j)erceiving it, or being able to find it again when they have 

 left it ; the rapid search for a hole in the soil is explicable, not only as a 

 flight from the light, but as an expression of the necessity for a damp 

 environment, with which the greater part of their body may be in direct 

 contact. 



* Atti Accad. Gioenia-Sci. Nut. Catania, xix. (188r)). Cf. Kev. Ital. Sci. Nat., 

 ii. (188(5) pp. 92-4. 



t Comptes Rendus, ciii. (1886) pp. 1200-3. 



j Journ. de I'Anat. et de la Physiol., xxii. (1886) pp. 431-57. 



