G. H. F. Nuttall 
23 
REGENERATION OF LEGS. 
Argas persicus. It was found that when freshly gorged larvae had their 
legs amputated, the corresponding limbs were not regenerated in the first 
nymphal stage, but when these nymphs were fed and allowed to undergo 
a further moult without operative interference, they regenerated these muti¬ 
lated limbs perfectly. When first-stage nymphs, under like conditions, were 
similarly mutilated, they gave rise to second-stage nymphs with well-formed 
legs of subnormal size. These results are in conformity with those of Hindle 
and Cunliffe (cited on p. 7) who explain the difference in the results obtained 
with larvae and nymphs by an interesting observation on larvae subjected to 
operations made at an earlier stage whilst still feeding on the host. When 
replete larvae abandon the host, they are well advanced in their nymphal 
development, and, consequently, if they are operated upon at this stage, they 
do not regenerate their legs, the first-stage nymphal formative tissues having 
been injured. 
Amblyomma hebraeum. My experiments on this species show that when 
the legs are mutilated in replete larvae or nymphs immediately after the 
ticks have abandoned the host, the limbs are regenerated in the succeeding 
stage; in one adult that developed from a nymph which had been mutilated, 
the regenerated limbs were slightly smaller than normal, in the remaining 
six ticks the regenerated limbs were of normal size. 
Hyalomma aegyptium. Similar experiments of mine upon replete nymphs 
of this species show that the regenerated limbs in the adult may be either 
perfect or of subnormal size. 
Therefore 21 leg amputations in Ixodid ticks were followed in all cases by 
regeneration, 13 legs being normal and 8 slightly reduced in size. 
SUMMARY AND CONCLUSIONS. 
Amputation experiments upon immature stages of Argas persicus (Oken 
1818), Amblyomma hebraeum Koch 1844, and Hyalomma aegyptium (Linnaeus 
1746) show that the mouthparts and legs of these ticks may be more or less 
regenerated when mutilated shortly after the ticks have abandoned the host 
in a fully engorged condition. 
Regeneration of Mouthparts. 
In immature Argas persicus the mouthparts are regenerated more or less 
perfectly according to the structure affected and the stage of development of 
the tick. Freshly gorged larvae regenerate their mouthparts badly compared 
to first and second-stage nymphs because during their period of parasitism 
upon the host (5-6 days usually) the larvae have advanced well along the 
road to becoming nymphs, therefore the operation largely affects the forma¬ 
tive tissues of the developing nymph. The nymphs feed rapidly, usually in 
