Volume XII 
SEPTEMBER, 1920 
No. 3 
MALFORMATIONS IN TICKS. 
By L. E. ROBINSON, A.R.C.Sc. (Lond.). 
(From the Quick Laboratory , University of Cambridge.) 
(With 5 Text-figures.) 
In 1909, and again in 1914, papers, recording cases of deformity in Ticks, 
were contributed to this journal, by Warburton and Nuttall 1 , and Nuttall 2 , 
respectively: since that time, numerous examples of malformation have been 
observed in the material examined by them and by myself, in the course of 
our collaboration in work on Ticks in general. Of these examples, the five 
which are described and figured below, are sufficiently striking to be placed 
on record. The figures have been drawn with the aid of the Abbe-Zeiss camera 
lncida, and, in each case, the degree of magnification is indicated by a scale 
representing a length of one millimetre. 
Specimen 1. 
Dermacentor atrosignatus Neumann, 1906, taken off a dog, at Kosempo, 
Formosa, collector’s name not recorded. The specimen was received, on loan, 
from Prof. L. G. Neumann, and was derived, in the first instance, from the 
collection of the Deutsches Entomologisches Museum, Berlin. With the 
exception of the hypostome, the tick is normal in all respects. The hypostome 
shows a considerable degree of asymmetry, due to an antero-mesial displace¬ 
ment of the denticles on the left side. The non-denticular proximal portion 
exhibits an anomalous feature, in that it bears three forwardly-directed salient 
points; these are clearly displayed in the figure. 
Specimen 2. 
Amblyomma hebraeum Koch, 1844, $ (N. 2413 a). The specimen was found 
on a cow (28. vii. 1913), at Namahacha, Portuguese East Africa, and is the 
! gift of Dr J. B. Botelho. The scutum is not only deformed, bub is remarkably 
small for the species, its length measuring barely two-thirds of the length of 
a normal example. The eye is absent on the left side, and, immediately 
1 Warburton, C. and Nuttall, G. H. F. (1909), On new species of Ixodidae, etc., Parasitology , 
n. 57-76. 
2 Nuttall, G. H. F. (1915), Tick abnormalities, Ibid. vn. 250-257. 
Parasitology xn 1 •> 
