ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 503 



them, especially species of Aschersonia, being very widely distributed and 

 of considerable economic importance in combating insect pests in districts 

 where the proper conditions of temperature and moisture are present. 

 Cultures were made of the fungi, and their life-histories studied ; the 

 larvae of Alcyrodes were successfully infected from cultures. In addition 

 to the destruction wrought by the insects, much harm is done to the 

 Citrus trees by the fungus Meliola, a sooty mould that lives on their 

 sugary excretions ; it smothers the leaves of the plants by a felt of 

 black nryceliuin. If the insects are killed this fungus also disappears. 



Destruction of Harmful Insects by Fungi.* — J. Gamara Pestana 

 found a parasitic insect {Lecanium hesperidum) inhabiting an ornamental 

 plant {MuklmbecMa plateclata), which had already been attacked and 

 destroyed by a fungus. The parasite of the insect proved on examination 

 to be Sporotrichum gloiuliferum, discovered first by Spegazzini in Cali- 

 fornia on some Coleoptera, and since then detected on other insects, a list 

 of which is given. The fungus never attacks the plant. Pestana 

 describes the methods of culture and insect-inoculation which he recom- 

 mends as a means of checking their multiplication. 



Parasitism of Fungi.f — E. W. Schmidt has attacked the problem 

 of chemotropic attraction in the host-plant inducing growth in the 

 parasite. He tested the power of the hyphaa to bore through various 

 membranes, such as celloidin, influenced by chemotropic substances. 

 This he proved satisfactorily, but he demonstrates that the germinating 

 spore must by enzymatic, toxic or mechanical action, alter the structure 

 of the epidermis and cells, in order to set free a diffusion-stream which 

 acts as a directing agent on the forward growth of the fungus. 



Fungi of Seeds.1: — Franz Muth has classified the fungi that attack 

 germinating seeds in testing beds, and finds that those of most frequent 

 occurrence are Rhizopus nigricans and Cephalothecium roseum., which 

 came from the surrounding atmosphere ; the parasitic fungi, as for in- 

 stance Phoma Betse, Ascochyta Pisi, Fusarium vasinfectum, are also 

 found on the seeds ; other fungi are due to special circumstances 

 affecting the seed-bed, etc., and certain bacilli are present in the water 

 used for keeping the seeds moist. The author discusses the significance 

 of these fungi for germinating seeds. 



Edible Mushrooms. § — W. A. Murrill writes more particularly of 

 those that grow in Bronx Park, New York, but most of the species that 

 are exceptionally valuable for their culinary properties are described by 

 him. He warns collectors very carefully against the deadly Amanita, 

 which has neither a bad taste nor offensive smell to indicate its 

 poisonous qualities. Special attention is drawn to the wholesome nature 

 of puff-balls when young. He advises beginners to confine themselves 

 at first to the common mushroom, the beef -steak fungus, the puff-balls, 

 the coral mushrooms, and other readily recognisable forms. 



* Bull. Soc. Port. Sci. Nat., ii. (190S) pp. 14-18 (1 pi.). 

 t Zeitschr. Pflanzenkr., xix. (1909) pp. 129-43 (7 figs.). 



% Jahresber. Ver. Ang.Bot., v. (1908) p. 49. See also Arm. Mycol., vii. (1909) 

 pp. 206-8. § Joum. New York Bot. Gard. is. (1908) pp. 205-13 (2 pis.). 



