386 



escapes by perforating the corolla in search of further food. The 

 flowers so attacked do not open again and rapidly wither. From 

 caterpillars reared in captivity, the Tachinid, ZeniUia roseanae, B. B., 

 was bred. The emergence of the adults of the parasite and of uninfested 

 individuals of G. nnionalis was simultaneous. The Tachinid evidently 

 oviposits on the flowers, and some of the eggs are swallowed by the 

 larvae of the host. G. nnionalis is more generally known as an olive 

 pest. 



Thompson (W. R.). Theorie de I'Action des Parasites entomophages. 

 Les Formules mathematiques du Parasitisme cy clique. — C.R. 



Hehdom. Acad. Sci., Paris, clxxiv, no. 18, 1st Mav 1922, pp. 

 1201-1204. 



An attempt is made to devise mathematical formulae to indicate 

 the activities of entomophagous parasites that may be expected at 

 any given time 



Hassox (J.). Bekampfung tieriseher Sehadlinge durch Vergasung 



des Bodens. [The Control of Animal Pests by Fumigation of the 

 Ground.] — Wien. landu'. Zeitg., Ixx, 1920, p. 471. (Abstract 

 in Centralhl. Bakt., Paras. Infektionskr., Jena, lite Abt., Ivi, 

 no. 5-13, 26th May 1922, p. 194.) 



In these experiments a field infested by larvae of Agriotcs and other 

 pests was fumigated with chloropicrin by means of a special apparatus. 

 It comprises a container, placed on the front of an ordinary plough 

 and fitted with an air pump worked by a rod connected with one of 

 the wheels and with pipes to a series of five nozzles, any one of which 

 can be shut off. These nozzles spray the chloropicrin on the earth 

 turned up in the preceding furrow, on the sods that are being turned 

 over and on all parts of the furrow. All pests are destroj^ed, but it 

 is not known whether useful bacteria share the same fate. The 

 apparatus uses about If pints of chloropicrin a minute. 



Herrmann (F.). Untersuehungen iiber die Wirkung von Arsensalzen 

 als insektentotende Mittel. [Investigations on the Action of 

 Arsenical Salts as Insecticides.] — Ber. d. hoh. Sfaatl. Lehranst. 

 Ohst- u. Gartenb. Proskau f. 1918-1919, Berlin, 1921, pp. 99-105. 

 (Abstract in Centralbl. Bakt., Paras. Infektionskr., Jena, Ilte 

 Abt., Ivi, no. 5-13, 26th May 1922, pp. 198-199.) 



A 3 per mille strength of Urania green produces marked spots 

 on the leaves of apple and pear and turns the edges of oak leaves 

 brown. These effects are also produced by a 4 per cent, strength 

 of barium chloride. Even a weak solution of Paris green causes 

 yet more injury if spraying is followed by dry, sunny weather. This 

 is not the case with lead arsenate, even of ^ per cent, strength. 



Schmidt (C. W.). Cahren-Fango, ein neues Mittel gegen Bekampfung 

 sehadlicher Insekten im Garten und Feld. [Cahren-fango, a new 

 Material for combating Injurious Insects in the Garden and Field.] 

 — Der Lehrmeister i. Garten u. Kleinticrhof, xviii, 1920, p. 258. 

 (Abstract in Centralbl. Bakt., Paras. Infektionskr., Jena, Ilte 

 Abt., Ivi, no. 5-13, 26th May 1922, p. 199.) 



Cahren-fango is a dried and powdered mineral mud from the Eifel 

 region. It is used as a dust and acts by clogging the respiratory 

 apertures of insects. 



