354 
Mcillophaga from Marsupials 
We find this species to he generally distributed upon the genus 
Macropus. Piaget originally described it from Macropus giganteus in 
the Rotterdam Zoo. We have it from the following hosts: Macropus 
thetidis, Queensland, N. S. Wales; M. ualabatus, Victoria; M. ruficollis. 
Flinders Island; M. bennetti, Melbourne Zoological Gardens; M. dorsalis, 
N. S. Wales; M. rufus, N. S. Wales; M. robustus, N. S. Wales; M. 
giganteus, N. S. Wales, Queensland; M. wilcoxi, N. S. Wales; and M. 
stigmaticus, Queensland. It has, in addition, been recorded from dogs 
from several localities in America and Africa, as well as from Japan; 
and from a jackal from Africa. This extraordinary host distribution 
has led Paine ( loc. cit.) to claim that Heterodoxus is “characteristic of 
dogs.” Such is certainly not the case. It is undoubtedly a marsupial 
parasite, and all occurrences on carnivora must be ascribed to straggling. 
The species presents considerable difficulty for the systematic 
worker, as the range of variation is very considerable. Possibly at 
a later date characters may be found which will justify a splitting up, 
but we do not feel inclined to attempt this step at present; for, although 
forms from certain hosts seem quite distinct if examined alone, inter¬ 
mediate forms can be found upon other hosts, which connect them back 
with typical longitarsus. Curiously enough, the chaetotaxy of the dorsal 
surface shows a very remarkable uniformity. But we have found great 
variation, which we thought at first was going to give us characters of 
diagnostic value, in the chaetotaxy of the thoracic sternites. The 
variation here, however, finally baffled us. But we would draw attention 
to these plates, and to the genitalia, in which we have also observed 
differences, as likely to afford a solution. 
H. armiferus Paine has been included as a synonym, because there 
is nothing in Paine’s description or figures that we allow to have dia¬ 
gnostic value. It is quite possible, however, that this is really a distinct 
species, and we think it may even prove to be characteristic of 
some American marsupial host. We have examined the African and 
Yokohama specimens from dogs, and consider them to be indubitable 
stragglers from Australian marsupials. 
Our figure of the head and thorax is drawn from a typical specimen 
from Macropus ualabatus. The proportions of the head and thorax 
vary somewhat according to the amount of pressure employed in mount¬ 
ing ; a fact which accounts for the minor differences in various published 
figures. 
