49 SUMMARY OF CURRENT RESEARCHES RELATING TO 



points out that his results do not support the view that the regenerative 

 capacity is always adaptive. The regenerating organ is internal and 

 could hardly be injured without destroying the whole animal, though 

 this was not the result in the author's hands. Removal of the gonads, 

 or their exchange with those of another sex, does not affect the secondary 

 sexual characters in the regenerated wing. 



Polar Body Formation in Ant.* — W. Schleip has studied Formica 

 sanguinm. There are about forty-eight chromosomes in the first seg- 

 mentation-spindle ; in the equatorial plate of the first directive spindle 

 of the fertilised and of the parthenogenetic ovum there are about twenty- 

 four ; there is probably a pseudo-reduction (syndesis) in the prophase of 

 the first directive division, the twenty-four chromosomes of the first 

 directive spindle being interpreted as double-chromosomes. The polar 

 bodies come to nothing in the parthenogenetic as in the fertilised egg. 

 There is no " Richtungscopulationskern " as Petrunkewitsch believed. 



In the development of a parthenogenetic ovum there are various 

 possibilities as to the number of chromosomes. 1. There may be a 

 reduction, and the normal number may be restored by the second polar 

 nucleus uniting with the pronucleus (Artemia salina, observed by Brauer). 

 2. There may be reduction, and then the chromosomes may double 

 (Lasius niger and Rhodites rosce, observed by Henking). 3. There may 

 l>e reduction, and a Richtungscopulationskern with the normal number 

 is formed, from which the germ-cells are derived, while the chromosomes 

 double spontaneously in the pronucleus (Drone-eggs, observed by Petrun- 

 kewitsch). 4. There may be no reduction and no doubling (probably in 

 various saw-flies, Doncaster). 



In Formica sanguinea the egg develops, at least to the stage of the 

 germinal streak, with a reduced number of chromosomes. 



Leg Tendons of Insects.f — C. W. Woodworth has studied the 

 tendons, which are cuticular invaginations and subject to replacement 

 at each moult. They belong to the same set of internal processes as the 

 internal skeleton of the head and thorax, the tendons of the jaws, the 

 great internal disk-like tendons for the attachment of the elevator muscles 

 of the wings in Odonata, and the skeletal and tendinous process of the 

 ovipositor. 



Palaearctic TortricidEe.J — J. Kennel gives a monographic account 

 of this family of moths, describing their general structure and life- 

 history, sex-characters, variability, ethology, and systematic relationships. 

 The phylogeny is discussed and summed up in a very striking diagram- 

 matic plate. 



Philippine Cassididae. — J. Weise § describes some new Cassididas, 

 and W. Schultze || discusses some life-histories. After a careful inquiry 

 into the significance of the peculiar excremental coverings, filaments, or 



* Zool. Jahrb., xxvi. (1908) pp. 651-82 (2 pis.). 

 t Amer. Nat., xlii. (1908) pp. 452-6 (2 figs.). 



t Zoologica, xxi., heft 54 (1908) pp. 1-100 (6 pis.. 1 genealogical tree, and text- 

 figs.). § Philippine Journ. Sci., iii. (1908) pp. 259-60. 

 || Op. cit., pp. 261-71 (6 pis.). 



