61 



Caballero (A.). La Chara foetida A. Br., y las Larvas de Slcf/otmjia,. 

 Culex y Anopheles. Bol R. Soc. Espahola Hist. Nat., Madrid, 

 xix, no. 8, October 1919, pp. 449-455. 



The occurrence of larvae of Stegomyia in large numbers in some 

 tanks in which aquatic plants were being reared in the botanical 

 laboratory of the Barcelona University and their absence in others, 

 led to further investigations and experiments. It was found that 

 larvae of Stegomyia, Culex and Anopheles die in pools that contain a 

 certain quantity of the plant Cham foetida. The exact cjuantity 

 necessary to cause the death of all the larvae present has not been 

 determined, but it is evident that in 50 c.c. of water the mass of 

 vegetation must occupy somewhat more than ^ of the space, though 

 this proportion or even less is sufficient to prevent oviposition, and to 

 cause the death of some larvae and hinder greatly the development 

 of others. The effect on all three genera is very similar, though the 

 larvae of Ste/jomyia appear slightly more resistant than the others.. 

 C. foetida is easy and economical to grow, both in town and country. 



The cause of the toxicity to which this plant gives rise clearly lies 

 in the fact that if left uncovered, the surfaces of any water containing 

 the growing plant (piickly becomes covered with patches of a thin 

 oily substance, and this within three or four days forms a light film 

 deepening later to about h mm. in thickness. It is evident that the 

 presence of this film interferes with the respiration of the larvae. 



Brethes (J.). Sur la Prospalangia platensis (n. gen. n. sp.) (Hymen.) 

 et sa Biologie.— Anales Soc. Cien. Argentina, Buenos Aires, Ixxix, 

 no. 5-6, May-June 1915, pp. 314-320, 8 figs. 



A new Chalcid, Prospalangia platensis, gen. et sp. n., is here described. 

 It has been found parasitic upon the pupae of Musca domestica,, 

 Stonioxys calcitrans and other flies in the neighbourhood of Buenos 

 Aires. The larva feeds upon these Diptera within the puparium, where 

 pupation of the parasite also takes place. Although only one parasite 

 is found in each host, the percentage of parasitism, judging from the 

 author's observations, seems to be from 60 to 74 per cent. It is 

 thought therefore that this beneficial parasite may be of considerable 

 use if propagated as a control for M. domestica. 



JuNGMANN (P.). Untersuchungen uber SchsL^ausrickeitsien {RicJcettsia 

 melophagi, Noeller). [Rickettsia of Sheep Ticks.]- Deutsche Med. 

 WochenscJu:, Leipzic, xliv, no. 49, December 1918, pp. 1346— 

 1348. 



A Ricliettsia-Wke organism, Rickettsia melophagi, Noeller, is a normal 

 and regular inhabitant of the intestine of the sheep tick [Melophagus 

 ovinus]. It differs from the R. prowazeki found in Pediculus humanus 

 in the following particulars. It can be cultivated on sheep's blood- 

 glucose-agar, whereas up to now the artificial culture of R. prowazeki 

 has failed. It is, as a rule, an extra-cellular organism of the cells of 

 the stomach, whereas R. prowazeki is intra-cellular. It is a regular 

 intestinal parasite of Melophagus ovinus in which infection is trans- 

 mitted to the eggs, whereas R. prowazeki is probably accpiired by 

 P. humanus when the latter feeds on a typhus-infected man. 



