B14 



GEORGE H. F. NTJTTALL. 



The best way for the beginner to start the study of ticks is to collect specimens 

 and to submit them to a specialist for determination ; he will save much time by 

 so doing. When the specimens are returned they will serve as standards for com- 

 parison with any other specimens which may be collected. 



The subject of the biology of ticks, especially that of the species occurring in the 

 Congo, is fully dealt with and a short account is given of the diseases they convey. 



Those desiring more detailed information on the subjects treated of in this paper 

 are referred to Ticks, a Alonograph of the Ixodoidea, by Nuttall, Warburton, Robinson 

 and Cooper, Parts I, II, III, and the Bibliographies I and II accompanying this work ; 

 also to Parasitology, Vols. I-VIII. Both publications are from the University Press, 

 Cambridge. 



Classification. 



Ticks are Acarina belonging to the suborder Metastigmata, i.e., having their 

 respiratory apertures {stigma or spiracle) situated somewhat posteriorly on the body. 

 They possess a characteristic capitulum or false head (fig. 1) consisting of {a) basis 

 capituli, bearing (6) paired palps, (c) paired chelicerae with digits having outwardly 

 directed teeth, and (d) a ventrally toothed rigid hypostome. Ticks are blood-sucking 

 parasites of mammals, birds, terrestrial reptiles and amphibia. Some species are 

 only parasitic on birds, others on reptiles, others again may occur on mammals, birds 

 and reptiles. 



Palp article 4 

 Art. 3 



Internal] -J^>ol^,f 

 External \oFChelicera 



hypostome 



St)aft or 

 Chielicera 



Post-palpal 

 hair 



Post-hypostomal 

 hair 



Fig. 1. Argas persicus (Oken 1818) ^ : 

 capitulum in ventral aspect (Nuttall, 1908). 



Ticks constitute a superfamily, Ixodoidea, which contains two families, (1) 

 Argasidae and (2) Ixodidae. The most striking difference between these two 

 families (figs. 2 and 3) is the possession in Ixodidae of a hard scutum or shield which 

 covers the whole body of the male and the anterior part of the body in the female, 

 nymph and larva. The Argasidae have no such scutum, and the sexes are only 



