19 



by the sharp differentiation between the rainy and dry seasons. In 

 the districts visited the rains lasted from about the beginning of 

 December to the end of April, the average rainfall varying from 4 to 

 28 inches according to the locality. In western Outjo 16 inches may 

 be taken as a very good rainfall. This moderate amount of moisture 

 is followed by a dry period of from six to seven months. Furthermore 

 the night temperatm-es from May to August often drop to 0° C. [32° F.] 

 and sometimes still lower. Thus even during the months when ticks 

 were most numerous, from February to April, they were not obvious 

 on horses, cattle and other mammals. In the dry season (May to 

 September) many domestic animals and wild game especially are 

 entirely free from ticks. 



The following ticks are recorded, together with particulars of their 

 morphological characters and prevalence : — Argasidae : Argus persi- 

 cus, abundant in most fowl houses. Ixodidae : Aponomma exornatutn. 

 found in one locaHty. Hyalomma aegyptium, equally distributed 

 throughout the region visited. It was chiefly found, always in the 

 adult stage, on equines including zebras, cattle, sheep, goats, oryx 

 antelopes, small antelopes, wild pigs, dogs and man. Rhipicephalus 

 evertsi var, mimeticus, Don., is a very common tick on horses, cattle, 

 sheep and goats. Nymphs were also taken from cattle. As its 

 external characters have never been described, except very 

 briefly by Donitz, they are dealt with here. R. oculatus is widely 

 distributed. Its chief host is the hare, others in order of decreasing 

 importance being small antelopes, sheep, goats, dogs, equines including 

 zebras, and cattle. Nymphs were found on a dog and an ox. R. san- 

 guineus was found in two localities. The dog ic, the chief host, others 

 being equines, wild pigs and sheep. Rhipicentor bicornis is a parasite 

 of canine animals ; it was never found on goats. The specimens 

 were always somewhat smaller than as described by Donitz after 

 Nuttall and Warburton. One female of Hattnaphysalis leachi was 

 taken from a dog. On the whole, ticks in this region cause much 

 less damage than in other countries, chiefly owing to their small 

 numbers. 



SwELLENGREBEL (N. H.). De Anophelineii van Nederlandsch Oost- 

 Indie. [The Anophelines of the Dutch East Indies.]— Eoloniaal 

 Insiituut te Amsterdam, Meded. no. vii, Afdeeling Trop. 

 Hygiene no. 3, 1916, 182 pp., numerous text-figures, 16 plates. 

 Price fl. 4.50. [Keceived 6th November 1918.] 



This detailed review of the Anophelines fomid in the Dutch East 

 Indies has been published in consequence of the literature on the 

 subject being very complicated owing to the lack of agreement between 

 the work of Donitz and Theobald, and the author hopes that it will 

 assist to render civil medical officers in the Dutch East Indies inde- 

 pendent of European specialists in the identification of the various 

 species concerned. The structure of the Anophelines is described and 

 keys are given to the species known from the Dutch East Indies, as 

 well as to the more important ones from south-eastern A sia. Practical 

 hints on identification are added and the bulk of the volume is 

 occupied with descriptions of the various genera and species. 



