24 SUiMMARY OF CURRENT RESEARCHES RELATING TO 



monograph is a " gekronte Preisschrift " of the German Entomological 

 Society. 



Supposed Numerical Preponderance of Males in Odonata.* — 

 E. J. Tillyard maintains that the prevailing view that there are far 

 more males than females among Odonata is fallacious. The males are 

 more conspicuous, more brilliant, more frequently on the wing, more 

 diurnal, and therefore more likely to be collected. The females often 

 live apart from the males, and live a more retired life. By rearing 

 nymphs of Lestes leda, a common Agrionid around Sydney, the author 

 found that the ratio of the sexes was one of equality. 



Dimorphism in Female of Ischnura heterosticta.f — R. J. Tillyard 

 describes the two forms of the female in this dragon-fly. The genus 

 Ischnura consists of very fragile and defenceless forms, with limited 

 powers of flight, and it seems probable that the second form of female, 

 which is very like the male, may in some manner help to prevent 

 extermination by deceiving enemies. The case is a very interesting one. 



Phosphorescent Collembola.J — F. Ludwig calls attention to the 

 frequent occurrence of Sminthurus bicinctus and Entomobrya on Hdle- 

 borus fcetidus and other plants. He suggests that the luminosity of 

 some flowers and leaves may be due to Collembola, in some of which, 

 e.g., Aphorura fimetaria, A. armata, and Neanura museorum, phos- 

 phorescence has been proved. 



y. Myriopoda. 



Variation in Scutigera.§ — K. W. Verhoeff gives numerous details 

 regarding the variability of Thereuoncma species. He found this very 

 marked in forms from China and Japan, where it occurs even in 

 oppositely placed parts in an individual. It is greater in the segments 

 of the antennas than in those of the tarsus. A number of cases of 

 discontinuous variation in the tarsal elements of various Scutigera 

 genera are described. 



5. Arachnida. 



New Excretory Organ in Hydrachnids.||— Karel Thon describes in 

 Limnochares and Eulais a coxal excretory organ in the region of the 

 second coxa. A number of wedge-like bipolar cells (schedocytes) form 

 a spherical group round a small lumen with a simple efferent duct. 

 The formation of the intracellular excretory granules is described in 

 detail. In Eulais the organs are most active in the nymph period, and 

 degenerate in the adult when the proctodaeal excretory organs begin to 

 function. In Limnochares the coxal organs continue to function 

 actively in adult life. 



Arachnological Notes.1T — F. Silvestri describes the young female 

 and the male of that interesting primitive type, Kcenenia mirabilis, and 



* Proc. Linn. Soc. N.S. Wales, xxx. (1905) pp. 344-9. 

 t Tom. cit., pp. 302-6. 



% Prometheus, vii. (1904) pp. 103-7. See also Centralbl. Bakt. Parasit., xiv. 

 (1905) pp. 659-60. § Zool. Anzeig., xxix. (1905) pp. 353-71. 



|| Zeitschr. wiss. Zool., lxxix. (1905) pp. 465-95 (1 pi). 

 H Redia, ii. (1905) pp. 239-61 (4 pis ). 



