182 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Palmen's Organ in Ephemerids.* — J. Gross discusses this remark- 

 able structure in Ephemera vulgata L. It is a roundish body, with 

 •concentric layers of chitin, and lies on the roof of the head where four 

 tracheae meet. No nerve endings were found, but the suggestion is 

 made that the puzzling structure may be an equilibrating or orientating 



organ. 



Monograph on Lepismatidse.t — K. Escherich has supplied a much- 

 needed critical monograph on this family of Thysanura, which is so 

 important in relation to higher insects. He discusses the segmentation 

 of the body, the integument with its scales, bristles, teeth and spines, 

 and the various appendages. There is an interesting chapter on habits, 

 both of those which live freely and of those which live in association with 

 ants and termites. Those which occur in houses — Lepisma saccharina, 

 'rhmnobia domestica, and Acrotelsa collar is — are especially referred to. 

 The bulk of the memoir is, of course, systematic. The first subfamily, 

 Lepismatinrc, includes Lepisma, Isolepisma, g. n., Heterolepisma, g. n., 

 Silvestrella, g. n., Braunsina, g. n., Lepismina, Ctenolepisma, g. n., 

 Tiiermooia and Acrotelsa, g. n. The second sub-family Nicoletiinae 

 includes Atelura, Lepidospora, g. n., Nicoletia and Trinemophora. The 

 third sub-family Maindroniinas includes the single genus Maindronia. 



Collembola of Lapland. | — H. Agren reports on the first collection 

 of Collembola from Lapland. It Avas made by S. Bengtsson in 11)03. 

 Twelve species occur in Lapland which are known from the Palrcarctic 

 region generally ; Isotoma bidenticulata is restricted to Arctic and 

 Alpine areas ; nine species occur which have hitherto been known only 

 from regions to the south of Lapland ; Achorutes lapponicus Axels, and 

 six new species, may be provisionally regarded as characteristic of 

 Lapland ; but no specifically Arctic species was discovered. 



Ventral Tube of Tomoceros.§ — E. W. Hoffmann describes in con- 

 siderable detail the structure and relations to the head glands of this 

 tube which develops from a pair of abdominal legs. It functions mainly 

 as an adhesive organ, but appears to be capable of assisting in respira- 

 tion. 



8. Arachnida. 



Spiders of the Erigone Group.|| — Frank P. Smith indicates the 

 extent and constitution of the "Erigone Group" of British spiders, 

 embracing the genera (Edothorax, Stylothorax, Coryphcms, Gongylidium, 

 Gongydiellum, Trachygnatha, Erigonidium g. n., Gonatium, Enydia 

 (nomen novum), Falconeria g. n., Dismodicus, and Typlioclirozstus. 



Fossil Scorpion from Lancashire.1T — W. Baldwin and "W. H. Sut- 

 cliffe describe from the middle coal-measures of Lancashire, near Boch- 

 dale, a new species of scorpion, Eoscorpius spartliensis. The specimen 

 occurred within a clay-ironstone nodule. The authors make some com- 



* Zool. Jahrb., xix. (1903) pp. 91-106 (1 pi. and 3 figs.). 

 + Zoologica, xviii. (1905) heft 43, pp. 1-164 (4 pis. and 67 figs.). 

 \ Arkivf. Zool. (K. Svenska Vetensk. Akad.) ii. (1904) pp. 1-30 (2 pis.). 

 § Zool. Anzeig., xxviii. (1904) pp. 87-116. 

 || Journ. Quekett Micr. Club, ix. (1904) pp. 109-16. 

 t Quart. Journ. Geol. Soc. (1904) pp. 394-9. 



