ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 299 



Circulation in Insect Larvae.* — A. Popovici-Baznosanu describes in 

 the larva of Chloe, Siphlurus, and Tricorythus a ventral thoracic sinus 

 identical with the abdominal sinus of Graber. The blood is passed from 

 the sinus into the abdomen by the contractions of the ventral muscles. 



Insect Bionomics.t — F. Merrifield discusses a number of factors 

 affecting insect life. With a view to guiding inquiry and to rendering 

 our knowledge more complete, he suggests consideration of the following 

 propositions : — In the life-history of a species, the number of its 

 offspring should be observed and recorded. The consumption by 

 herbivorous insects of their food supply is not, except under special 

 circumsttmces, a cause of the extinction or permanent reduction in 

 numbers of a species. Mutual competition is not usually of primary 

 importance in keeping down the numbers of a herbivorous species of 

 insect : the chief factors are their active enemies. Insects, being 

 endowed with nervous matter controlling or guiding their movements, 

 are in their habits and activities affected by a psychic factor which must 

 be taken into account. Observation and record of the abundance or 

 scarcity of a species or variety, either generally or locally, and evidence 

 of the processes by which the balance of organisms as affecting 

 herbivorous insects is secured, are desirable. Factors which may have 

 selection value are polymorphism, scarcity, habits, etc. On the other 

 hand, a large number of conspicuous features, sufficient in themselves for 

 selection, are not, in fact, selected, but persist irrespectively of it. 



Natural Colour of Green Silk.| — R. Dubois applies the name 

 chloroyamamaine to a crystallisable green substance wliich he isolated 

 from the cocoons of Saturnia Yama-mai, and which is to be distin- 

 guished from an associated blue substance (cyanoyamamaine). While 

 Levrat and Conte regard the former as a chlorophyll, the opposite view 

 is maintained by Yillard. 



Rectal Respiration in Simulium.§ — E. Roubaud describes in the 

 larvae of SimuUum damnosum in Central Africa exsertile rectal branchiae, 

 which he regards as supplementing the insufficient cutaneous respira- 

 tion, and as a special adaptation to life in the water of warm countries. 



An Interesting Musoid.|l — J. Kiinckel d'Herculais discusses 

 Anthomyia (Chortophila) ciUcrura Rondani {= A. cana Macquart, and 

 A, peshawarensis Bigot), a minute Muscid which occurs in North 

 America, Algeria, India, South America, in fact almost everywhere, and 

 is most destructive of the ova of locusts and their allies in which the 

 larvse are parasitic. It turns out, however, that the larvae are in 

 certain conditions vegetarian, and are found attacking onions and the 

 like, which accounts for the world-wide distribution. 



Blastophaga and the Fig.f — Leclerc du Sablon describes what 

 happens when a Blasto2)haga lays an egg in figs of the third crop. The 



* C.R. Soc. Biol. Paris, Ixii. (1907) pp. 20-1. 

 t Trans. Entom. Soc. London, 1906, pp. cxiii.-cxliii. 

 X C.R. Soc. Biol. Paris, Ixii. (1907) pp. 52-4. 

 . § Comptes Rendus, cxliv. (1907) pp. 716-17. 



II Tom. cit., pp. 390-3. • f Tom. cit., pp. 146-8. 



X 2 



