ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 421 



of species. The authors refer to an Acarus found upon different 

 species of Cidex, to which they attribute no injurious effect upon the 

 host. An account is given of experiments with various substances with 

 a view to checking development. Of these meUoform appears to be the 

 most satisfactory. A • 05 p.c. sohition checks the development of Culex 

 larvfe. Pupge may develop imagines, but these often cannot leave the 

 pupa-case, and perish on the surface of the water. 



Notes on Life-history of Trochilium andrenseforme.* — N. Charles 

 Eothschild records the occurrence of several examples of the larva of 

 this Sesiid, which were found mining in the stems of Vihurnum lantana. 

 The insect makes a straight mine in the centre of the twig ; there is 

 an opening at right angles to the mine from which the larval " frass " 

 exudes and the insect emerges. The structure and habits of this larva 

 are described by Eustace R. Banks, and T. A. Chapman contributes a 

 note on the pupa. 



Bionomics of Insect Pests of Olive.f — F. Silvestri and G, Martelli 

 discuss fully the problem of fly -pests of the olive. Accounts are given 

 of their feeding, pairing, oviposition, tunnelling, etc., as well as full 

 descriptions of the various Hymenopterous insects which are parasitic 

 upon them. Particular stress is laid upon this aspect of the problem ; 

 analytical tables for the determination of the larva, pups, and adults 

 are supplied, and the question of multiplying them and the method of 

 utilising them are discussed. 



Argentine Sphecidse.J^ — H. T. Fernald describes a collection of 

 Sphecidse from Argentine which is now in Harvard Museum. Several 

 new species are indicated, and notes supplied regarding synonymy and 

 variability in others. 



Miillerian Mimicry in Butterflies of British Guiana.§ — W. J. Kaye 

 discusses along with full descriptions a number of cases from the Potaro 

 district, British Guiana. The general conclusion is arrived at that 

 " It must have been quite impossible for Nature to have evolved such 

 minutely close resemblance in unrelated groups without the aid of 

 Miillerian mimicry. It is impossible to imagine that, say, an Erycinid 

 butterfly, Esthemopsis sericina, should have arrived at the identical colour 

 and markings of a Syntomid moth, Agyrta micilia, purely and simply 

 by a process of syncriptic selection. It is the minutest details in the 

 coloration that dispel such a probability." That the butterflies settled 

 on flowers " unsuitable " for their protection was further definitely 

 proved. 



Spermatogenesis of Blatta germanica.]] — A. Wassilieff has inves- 

 tigated this subject. In the spermatogonia and young spermatocytes 

 there is a double nucleolus. The centrosome in the spermatogonia is 

 punctiform. The young spermatocytes attempt division, which is 



* Trans. Entom. Soc. London, 1906, pp. 471-82 (1 pi.). 



t Boll, del Lab. di Zool. gen. e agraria Firenze, ii. (1907) pp. 1-82. 



X Bull. Mus. Comp. Zool. Harvard, 1. (1907) pp. 263-72. 



§ Trans. Entom. Soc. Loudon, 1906, pp. 411-39 (5 pis.). 



II Arch. Mikr. Anat., Ixx. (1907) pp. 1-42 (3 pis.). 



