1948] 
Anastos — Parasitism of a Tick 
37 
species. Their final record was of two female Derma- 
centor andersoni ( Dermacentor venustus ) taken oft a 
horse at Lakeside, Washington; when received in the lab- 
oratory the smaller female was attached to the more fully 
engorged one. Sergent (1930, Bull. Soc. Hist. Nat. Afr. 
dn Nord XXI, p. 195) observed, in tick feeding experi- 
ments on a calf, that an nnengorged nymph of Hyalomma 
mauritanicum attached itself to an engorged nymph of the 
same species. Roubaud and Colas-Belcour (1935, Ann. 
Parasit. Paris, T13 No. 5, p. 427) record two males of 
Aponomma crassipes on a female of the same species 
taken oft a lizard in Tonkin, Indo-China. E. Francis 
(1938, Pub. Hlth. Rep., U. S. Pub. Hlth. Serv. 53, p. 2234) 
records a starved female Ornithodoros turicata attached 
and feeding on a fully engorged male, and an unfed 
fourth stage nymph feeding on a fed nymph of this same 
species. Gr. E. Davis (1941, Journal of Parasitology 27, 
p. 432) believes the term “cannibalism” to be a misnomer 
since the tick host is not consumed nor harmed enough to 
interfere with its normal functions. He records two 
cases wherein last stage nymphs of Ornithodoros parkeri 
were punctured by ticks which proceeded to completely 
engorge. 
From the small number of known cases it would appear 
that ticks seldom feed on each other. Lack of a suitable 
host in nature might induce a tick to feed upon an already 
engorged tick ; or else a tick might accidentally pierce an- 
other tick if the host were heavily infested. 
