192 



the young before causing death, the vitamines in the food having 

 been destroyed by heat. This is explained by assuming that 

 sterilisation destroys the symbiotes in the food, and consequently, 

 those in the tissues not being replaced, these latter gradually 

 degenerate and lose their synthetic function, and the condition 

 induced by lack of vitamines results. 



Organisms that in a state of nature live on substances lacking 

 symbiotes, such as xylopliagous larvae, Aphids, etc., possess a highly 

 specialised symbiotic mechanism, that is, they eat a cryptogamic 

 symbiote-carrier developed at the expense of the woody substances, 

 or their tissues contain enclosed micro-organisms, capable of hereditary 

 transmission. Former research has shown that the epithelial cells of 

 the intestine enclose corpuscles, which are in reality symbiotic micro- 

 organisms. To test the above theory larvae of Tenebrio molitor 

 (meal-worm) were experimentally fed on nourishment sterilised at 

 130°, and these not only grew as rapidly as those normally fed, in 

 some cases doubling their weight in three days, but also developed 

 into normal adults. 



Chalot (C.) & Bernard (U.). Culture et Preparation de la Vanille. 

 [Cultivation and Preparation of Vanilla.] — VAgron. Colon., Paris, 

 iii, no. 21, November-December 1918, pp. 72-86. [Received 

 18th February 1919.] 



The insect pests of vanilla in the island of Reunion include the 

 Psyllid, Trioza litseae, Giard, a most destructive pest, which attacks 

 the flower-buds and flowers, often preventing the development of the 

 fruit. Since its alternative food- plant is Litsea laurifolia, the best 

 remedy is the destruction of all trees of this species in the neighbour- 

 hood of vanilla plantations. Nezara smaragdula, F. (emerald bug) 

 sucks the sap from the stem and the floral buds, though the damage 

 done by it is unimportant compared with that of T. litseae. 



Injurious Lepidoptera include Conchylis vanillana, the larva of 

 which attacks the young fruit shortly after fertilisation, either killing 

 it or causing a great depreciation in its value. Since the eggs are laid 

 on the corolla of the vanilla flower after fertiUsation has been effected 

 and when it is beginning to wither, the simple and obvious remedy is 

 to remove the floral leaves immediately after fertilisation. Simplicia 

 inarcualis, Guen., and Phytometra (Plusia) aurifera, Hb., also 

 occasionally attack vanilla. Two Coleoptera, Hoplia retnsa, Klug, 

 and Cratopus punctum, F., frequently attack the corolla, sometimes, 

 destroying the fruit. The damage due to them, however, is shght 

 compared with that of the Curculionid, Perissoderes ruficollis, Waterh., 

 which in Madagascar mines longitudinal galleries often 20 inches long 

 in the stem, with the result that the area attacked blackens and dies. 

 The treatment recommended consists in carefully cutting and burning 

 the parts attacked without delay. 



In Madagascar, where Conchylis vanillana and Phytometra aurifera 

 also occur, their destruction by means of light-traps is recommended. 



Memmia vicina, to which attention has already been drawn [see 

 this Review, Ser. A, iii, p. 57], is a blackish Pentatomid bug which lives 

 under the leaves and attacks the flowers and fruits, causing them to 

 fall. It seems to appear at the rainy season, and to disappear at the. 



