542 



they recovered the following day. Quassiin powder dusted on web- 

 worms had the same effect on them, but caterpillars of Bomhyx mori, 

 L. (silkworm) were killed. 



Experimental tests for selection of effective formulae led to the 

 conclusion that in making the extract a relatively long period of 

 soaking is essential in order to get the maximum quantity of quassiin 

 in solution ; boiling the chips in water for 4 hours extracts 1| times 

 the amount obtained by soaking them in cold water for 24 hours ; 

 the smaller the chips and the finer the quassia powder used, the 

 greater the quantity of extract obtained ; the larger the quantity of 

 water used as a solvent^ the greater the quantity of extract ; the 

 addition of lye and soap to the water materially increases the effec- 

 tiveness of the extract. 



As regards the pharmacological effects of quassiin, it was found 

 that exhalations from quassiin powder killed Aphids, but that those 

 from quassia chips, quassia powder, and from solutions containing 

 quassiin extract and quassia extract were ineffective. It was also 

 shewn that quassia extracts affected Aphids only, and that quassiin 

 extract does not act as a stomach poison upon bees [Apis meUifica) 

 or Rhagoletis pomoneUa. Quassia powder dusted on insects had no 

 effect, but quassiin powder killed them by affecting the nervous system. 

 Quassia and quassiin spray solutions kill Aphids, if used sufficiently 

 strong, their effectiveness being increased by the addition of soap. 

 While nicotine acts quickly and causes pronounced symptoms, quassiin 

 acts very slowly and causes but few, feeble symptoms, the Aphids 

 slowly dying in a state resembhng coma. 



It is concluded that, owing to the poor iusecticidal properties of 

 quassiin and its expense, quassia extract can never become a general 

 insecticide for all Aphids. A spray solution made by soaking 22 lb. 

 quassia chips in 100 U.S. gals, fish-oil soap solution (1"6 lb. soap to 

 100 U.S. gals, water) for 24 hours, was efficient on only two out of 

 six species of Aphids tested, while the result was about equal to that 

 obtained by using nicotine sulphate solution ; the expense was nearly 

 the same, while o^^dng to its slower action it was much less reliable, 

 as a shower of rain or the migration of the Aphids nullifies its effect. 

 A bibHography of 48 works dating from 1779 is given. 



Keilin (M. D.). Sur un Nematode nouveau, Aproctonema entomopha- 

 gum, n. g. n. sp.. Parasite d'une Larve d'un Diptere. [A new 



Nematode, Aproctonema eniomophagmn, gen. et sp. n., parasitic 

 in a Dipterous Larva.] — C. R. Hebdom. Acad. Sciences, Paris, clxv, 

 no. 12, 17th September 1917, pp. 399-401. 



The larvae of Sciara pullida, Wimi., often contain the female of a 

 Nematode worm full of eggs, the parasite almost completely filling 

 the body-cavity of the larva. One or more males are also present 

 and fertilisation takes place within the body of the host. All the 

 parasitised adults of Sciara so far found have been females ; those 

 attacked late develop into nymphs and adults. At maturity the 

 female worm ruptures the skin of the host-larva, and escaping into 

 the gallery in the wood made by it, oviposits and dies. When the 

 parasite matures in the adult insect, it escapes by the rupture of 

 an inter- segmental membrane in the abdomen, which often results 



