No. 555] SPECIES-FORMING OF ECT0-PABAS1TES 141 



Seven species of Mallophaga have been taken from 

 four species out of the known five of the order Colymbi- 

 formes or loons, one of which is limited to the old world 

 with three circumpolar in range. On three of these loons 

 occurs the Mallophagan species Docopliorus cohjmb'uius, 

 and Nirmus frontalis is common to two, and Menopon tri- 

 dens to two. But the continuity of geographical range 

 among the loons does not seem to have produced any 

 special effect of commonness of parasites to different 

 host species. In the preceding order, for example, that 

 of the grebes, there is more commonness of Mallophagan 

 species, although at the same time more isolation of the 

 hosts geographically. 



From two penguins representing the order Sphenisci- 

 formes, three Mallophagan species have been recorded. 

 Two of these belong to the genus Goniodes, a genus best 

 represented among the pheasants and pigeons. The 

 third is type-species of a genus so far not elsewhere 

 recorded. 



The Procellariiformes, or petrels and albatrosses, of 

 which about a hundred living species are known, are rep- 

 resented in the host list by thirty-two species, and give 

 evidence of being a strongly parasitized group of birds. 

 Ten Mallophagan kinds have been taken from one species 

 of Puffinus, nine from another, eight from another and 

 seven from a fourth. Besides these, four other species 

 of Puffinus are in the host list. On the four Puffinus 

 species most infested there is one parasite kind common 

 to all, and four parasite species common to three of 

 them. Six species of albatrosses, genus Diomedea, are 

 included among the Procellariiform hosts. On five of 

 them occurs the giant Mallophagan species Lipeums 

 ferox, 10 mm. long, and on five also the large, broad 

 species Eurymetopus taurus. Nine species of Mallo- 

 Phaga have been recorded from the single albatross spe- 

 cies Diomedea albatrus, of the North Pacific Ocean. 

 Four Mallophagan genera, each of them containing but 

 a single species, are peculiar to the order. The birds of 



