182 



Sinclair (J. M.). Abridged Report of the Chief Veterinary Surgeon. — 



Sotithern Rhodesia Abridged Rept. Director Agric. for the Year 1917 , 

 [sine loco], 1918, pp. 4-6. [Eeceived 19th July 1918.] 



The number of fresh outbreaks of African coast fever during the 

 year was 13, with a mortality of 43 head, as compared with 20 and 

 382 respectively for the previous year. A new and very severe 

 outbreak occurred in the southern part of the Umtali district, due 

 to the movement of cattle from the southern part of Melsetter district 

 two years previously, the existence of infection during this period 

 having been masked by the use of a dipping tank. 



The supplementary report of the African Coast Fever Committee, 

 in dealing with the question of universal compulsory effective dipping, 

 emphasises the fact that though such dipping may prevent any 

 noticeable number of deaths when the disease exists, yet cattle moved 

 from such areas may, and have, carried infection with them. 



Wesenburg-Lund (C). Anatomical Description of the Larva of 

 Mansonia richiardii (Ficalbi) found in Danish Fresh waters. — 



Videnskabelige Meddelelser Dansk Naturhist. Kj0benhavn, Odense, 

 Ixix, 1918, pp. 277-328, 37 figs. [Eeceived 22nd July 1918.] 



The larvae of Taeniorhynchus {Mansonia) richiardii were found by 

 the author in some small ponds in September 1914. Only two larvae 

 of this genus have been described, viz : — Those of T. (M.) titillans, 

 Wlk., from S. America, and T. {M.) perturbans, Wlk., a North 

 American species known from Canada to Florida and westward as far 

 as British Columbia, and if not identical with, closely related to, 

 T. richiardii. 



The larvae of this genus differ from those of Culex in having the 

 siphon modified into a piercing organ by means of which living plant- 

 tissues are perforated and the inter-cellular air contained in them 

 is used for respiration. Hence the mode of hf e is quite dift'erent from 

 that of other mosquito larvae, since they are not free swimming but 

 sedentary, remaining attached to water-plants at the bottom of 

 shallow water, about one foot deep. 



Owing to the ponds being drained, the author was unable to rear 

 the adults, and it was not until three specimens were accidentally 

 found on the same spot, three years later, that the present paper 

 could be completed. 



Culicid larvae may be referred to four groups, according to their 

 method of respiration : — (1) Larvae that hang down from the surface 

 by means of the siphon and in this attitude breathe the atmospheric 

 air ; to this group belongs the great majority of Culicid larvae. 

 (2) Larvae that breathe the contained air of submerged plants by 

 means of different organs (the siphon in Taeniorhynchus, the antennae 

 in Aedomyia). (3) Larvae that live a pelagic life and mainly or exclu- 

 sively breathe dissolved air by means of the outer skin {Corethra, 

 Mochlonyx). (4) Larvae that possess air-tubes, but live mainly on 

 or near the bottom of stagnant pools and are furnished with very 

 lars;e gills. 



