ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 303 



The data tabulated and classified are derived from the study of twenty- 

 two genera, and a family diagnosis of fore and hind wings is given. 



&. Prototracheata. 



Monograph on Onychophora.* — E. L. Bouvier continues his mono- 

 graph on this interesting order, and deals with species of Peripatus, 

 Eoperipatus, Peripatoides, Paraperipatus, Opisthopatus, and Peripatopsis. 

 Special mention may be made of the very successful coloured plates. 



8. Arachnida. 



Habits of Pseudoscorpionidae.f — E. W. Berger gives an interesting 

 account of his observations on these animals, especially on Chelcmops 

 oblongus Say. Their wide distribution, especially north and south, is 

 probably due to their association with migratory insects. Their associa- 

 tion with insects takes various forms : simply for transport, or as com- 

 mensals, or as parasites. Most pseudoscorpions feed on the juices of 

 insects and mites smaller than themselves, but Berger found evidence of 

 cannibalism in Chelcmops. Casting or moulting nests are built by single 

 immature individuals for a safe retreat during moulting. Regeneration 

 of part of the pedipalps occurs. 



Coloured Skin Secretion in Opilionidae.J — J. C. C. Loman describes 

 from the skin of species of Gagrella a coloured secretion which is emitted 

 from the chitin pores. No trace of gland-cells could be found. Its 

 significance to the animal, whether protective in a similarly coloured en- 

 vironment, or rendering it nauseous to the taste, is undetermined. 



New Classification of Acarina.§ — A. C. Oudemans describes in 

 Labidostoma denticulatum the hitherto unknown tracheal system of 

 Labidostomida3. He found two dead specimens in which the soft parts 

 had rotted away, leaving (after the dorsal shield was removed) a fine 

 preparation of the tracheal system. The stigmata have a unique 

 position — beneath the mandibles, one on each side of the mouth. It is 

 interesting also to note that each specimen contained two fresh ova. 



A new classification of Acari is based on the trachea? and stigmata. 



Sub-class 1. Distigmata. 



Orders — Metastigmata, Mesostigmata, Parastigmata, 

 Antistigmata, Heterostigmata, Stoma- 

 tostigmata, and Prostigmata. 

 „ 2. Octostigmata. 



Order — Cryptostigmata (= Oribatidse). 

 „ 8. Astigmata (= Sarcoptidae). 



Orders — Diacrotricha, Monacrotricha, Anacro- 

 tricha. 

 „ 4. Lipostigmata. 



Order — Demodicides. 

 „ 5. Xemiostigmata. 



Order — Tetrapodili (= Eriophyidaa). 



* Ann. Sci. Nat. (Zool.) ii. (1905) pp. 241-383 (13 pis. and figs. 97-140). 

 t Ohio Naturalist, vi. (1905) pp. 407-19 (1 pi. and 1 fig.). 

 X Zool. Jahrb., xxii. (1905) pp. 755-8 (1 pi.). 

 § Zool. Anzeig., xxxix. (1906) pp. 633-7 (1 fig.). 



