714 SUMMARY OF CURRENT RESEARCHES RELATING TO 



white grub-like caterpillars emerge in about eight days, and almost 

 immediately begin to construct a shelter of silk, spun from a special 

 opening on the lower surface of the head, and strengthened with pieces 

 of wax. This shelter, which serves to protect them from the stings of 

 the bees, is gradually enlarged with the caterpillar's growth until it 

 becomes a kind of gallery connected with the exterior of a honeycomb. 

 The caterpillar creeps backwards and forwards along the gallery, but 

 never leaves it until it is about to spin its cocoon, when it makes its 

 way to the entrance opening of the hive. There it spins a cocoon, 

 which it attaches to the wall of the hive, generally beside many others, 

 so that they form a large compact mass. The winged insect emerges in 

 ten, fifteen, or eighteen days according to temperature, the optimum 

 temperature being apparently between 30° and 40° C. 



In regard to nutrition, it was found that the caterpillars fed chiefly 

 on the old broken-down pieces of honey-comb, and that this contained 

 larval skins, excrement of the bees, and other nitrogenous matter to the 

 amount of about 20 p.c. Artificially reared larvae, supplied only with 

 chemically pure wax, did not gain in weight or size, but went through 

 their whole metamorphosis, while those fed wholly on the nitrogenous 

 matter extracted from the wax, or on other substances, died very soon, 

 so that bees' wax is apparently the most indispensable element of their 

 dietary. One of the two constituent parts of wax, myricene and cerine, 

 was sufficient to keep the caterpillars in normal health, and either seemed 

 equally effective. 



The paper contains a full account of the structure and functions of 

 the digestive organs, and the anatomy and physiology of the three 

 systems of excretory organs — the Malpighian tubes, the pericardial cells, 

 and the phagocytes. In regard to these last, an interesting series of 

 experiments was made to determine how far the relative immunity of 

 the caterpillars to various pathogenic microbes was due to phago- 

 cytosis. The results showed three different cases : — 1. Phagocytosis 

 absent, or very feeble. In this case the caterpillars perished with sur- 

 prising rapidity. 2. Phagocytosis strong, but the phagocytes were 

 unable to digest the intruding bacteria. In this case the caterpillars 

 survived for a longer time, but ultimately succumbed to the disease. 

 3. Phagocytosis very vigorous, and destruction of the microbes within 

 the phagocytes. In this case the organism easily got over the disease, 

 and normal metamorphosis took place. 



Destruction of Book-worms.* — F. Secques discusses various methods 

 of destroying Anobium Mbliothecarum, Dorcatoma bibliothecarum, with- 

 out spoiling the books, and of sterilising books. He finds that exposure 

 in a metal box to vapour of formol is most effective. 



Flies in Amber, f — F. Meunier has studied more than 1500 speci- 

 mens of Baltic amber containing Diptera, and gives a monographic 

 account of the numerous genera and species of Empidae. All the species 

 seem to be extinct, but most of the genera are now represented in Prussia 

 and Xorth Europe generally. Among the most interesting genera may 



* Bull. Soc. Zool. France, xxxiii. (1908) pp. 112-14. 

 t Ann. Sci. Nat. (Zool.) vii. (1908) "pp. 81-135 (10 pis.). 



