THE MALLOPHAGA AS A POSSIBLE CLUE TO MRP PHYLOGENY. 11 



I have cited these two special casus as examples of the indications which appear from a 

 mere study of the distribution of mallophagan genera as at present constituted. Other 

 examples might be quoted, but would serve no particular purpose. 1 merely wish to draw 

 attention to certain features that exist, and to suggest the possibility of a valuable line of 

 study. Before anything in the way of appreciable results can be achieved, a much more cx- 

 ive examination of the Mallophaga will be necessary. Those of European and North 

 American birds are pretty well known. Dr. T. Harvey Johnston and myself have fairly con- 

 siderable Australian collections, not yet worked up. But for the rest of the world compara- 

 tively little has been done. Until more collecting, figuring, and describing has been clone, it 

 will be impossible to make satisfactory comparisons and to straighten out the inter-relation- 

 ships of the Mallophaga themselves. Moreover, many of the present genera are really family 

 ernii|i>. and until they are split up in accordance with more recent knowledge of structure they 

 are of little use as a basis of comparison. 



Work on the Mallophaga is being carried on continuously by various workers — Professor 

 Kellogg at the Iceland Stanford University; Professor Neumann at Toulouse; Dr. Mjoberg 

 in Stockholm; Dr. Johnston and myself in Australia. I should like to suggest to those in a 

 position to obtain Mallophaga, which are very easily collected from bird or mammal hosts, 

 and simply preserved in tubes of alcohol, should collect these generally neglected insects, and 

 forward them to one of the workers mentioned. By this means the gaps in our knowledge may 

 gradually be filled. 



When our knowledge of the parasites is more nearly complete, I believe that it will be pos- 

 sible to shed some light on bird phylogeny. There will, of course, be considerable difficulties 

 to overcome, and some necessary precautions must be taken. The complete disappearance of 

 important connecting links may prevent a proper understanding of Mallophagan inter-relations. 

 And remarkable contrasts in the rate and direction of variation of Mallophagan species will 

 have to be in some degree accounted for. Why, for instance, has the common Lipeurus colitm- 

 bae of pigeons persisted unaltered upon practically all the Columbiformes of the world, while 

 species belonging to other genera found upon pigeons show a considerable amount of differ- 

 entiation? Many such questions will arise, the explanation of which does not seem easy. And 

 there is also the straggling difficulty. The genus Laemobothrium is found upon diurnal Acci- 

 pitres, and upon a number of waterfowl which in the ordinary course might form the food of 

 the larger hawks. The position of the Accipitres is entirely unknown. Possibly there is a 

 phyletic connection between them and the waterfowl. Equally possibly, the genus Laemoboth- 

 rutin may have straggled from one to the other, when some primitive hawk was engaged in 

 devouring a primitive waterfowl. This straggling would seem, however, to be fairly limited. 

 Kellogg certainly found a condition of promiscuous straggling upon the Galapagos birds, but 

 there the conditions are quite unusual. There does not appear to be much indication of it 

 when conditions are normal. The evidence afforded by the cuckoos is distinctly against it. 

 In the case of these birds, the parasites can only migrate from one host to another during the 

 very brief time occupied in copulation. Young cuckoos are much more likely to be infested by 

 parasites of the foster parents in whose nests they are reared. But no instance has been re- 

 corded of parasites of foster parents being found upon a cuckoo, and the cuckoo parasites man- 

 age to survive as a pure stock in spite of difficulties, although comparatively few individual 

 cuckoos are parasitized. 



LITERATURE LIST. 



1896. Kellogg — Proc. Calif. Acad. Sci., (2), vi.. p. 31. 



1002. Kellogg tand Kuwana — Proc. Wash. Acad. Sci., iv., p. 457. 



1913. Kellogg — Amer. Naturalist, xlvii., p. 129. 



1910. Mjoberg — Arkiv f. Zoologi, vi., No. 13. 



I9T2. Neumann — Arch. d. Parasitologic xv., p. 353. 



1880. Piaget — "Les Pediculines, Essai Monographique," Leiden, 1880. 



