832 SUMMABY OF CURRENT RESEARCHES RELATING TO 



Arthropoda. 

 a. lusecta. 



Flight of Insects.* — Dr. Amans in his extended paper describes 

 his examination of the structure of the thoi ax in ^schia, Sirex, and 

 Lociista, and discusses the views of previous authors on the subject 

 of the flight of insects. He considers that a rational theory of 

 flight can only be formulated after various dissections and numerous 

 experiments on the resistance of the air; the laws of the latter 

 are as yet very incompletely known, and as to anatomy, a know- 

 ledge of one animal hardly aflbrds a sufficient basis for a general 

 theory. For the investigation of preliminary problems ^schna is 

 specially well adapted, as it is probably the most swiftly flying of 

 insects, making, as it does, 28 vibrations a second. 



Antennary Rods of Vanessa lo.f— J. Chatin describes the cavities 

 found on the joints which form the tip of the antennas of this insect 

 as communicating with the exterior by means of a very narrow orifice, 

 •which does not open directly to the exterior, but is more or less 

 completely closed by cuticular ridges which approximate to and curve 

 towards one another. Some authors, indeed, report the presence of 

 an obturator membrane, but this is an appearance only, and seems to 

 be due to the disposition of these parts ; the rod or rods found in the 

 pit have a peripheral zone, within which is a quantity of finely 

 granular protoplasm ; it is only in the young that one can observe 

 the nucleus, as the raj^id formation of pigment obscures the relations 

 of this body ; the bodies that have been described as nucleoli are 

 due to the granulation of the protoplasm, and the subsequent con- 

 densation of the pigment into small ovoid masses. The rod may be 

 considered as a modified hypodermic cell of special function, and 

 particularly characterized by the prolongations at either end ; the 

 lower of these is indicated by the nerve-branches ; the upper appears 

 to undergo a special differentiation, the exact investigation of which 

 the author postpones for the present. 



;3. Myriopoda. 



Studies on the Myriopoda.J — A. S. Packard, jun., has a revision 

 of the Lysiopetalidfe, a family of Chilognathous Myriopods, to which 

 he was led by a study of the cave fauna of the United States. In a 

 systematic account of the genera and species we find a description of 

 the generic characters of a new type, for which the name of Cri/pto- 

 trichus is proposed, in reference to the minute size of the setfe, which 

 are difiicult to detect. After a note on the genus Cambala the author 

 makes some observations on the Morphology of the Myriopoda. 



The Chilognaths are proved by their embryology and morphology 

 and their close relationship to the Pauropoda to be the representatives 



♦ Kev. Sci. Nat., ii. (1883) pp. 4G9-90 (2 pis.). Comptes Eendus, xcvi. 

 (1883) p. 1072. 



t Comptes Reiidus, xcvii. (1883) pp. G77-9. 



J Proc. Aiucr. Philos. ^oc, xxi. (18S3) pp. 177-2(.;9, 



