No. 555] SPECIES-FORMING OF ECTO-PARASITES 153 



species, two of which are North American, one Central 

 American, and one common to both old and new worlds. 

 Docophorous communis and Xirmus hrachy thorax occur 

 on three of the four species. 



Mallophaga have been recorded from eight species of 

 Laniidaa, or shrikes, of which three are old world species, 

 three new world and two are Australian. Docophorus 

 communis occurs on five of the old and new world spe- 

 cies, but not on either of the Australian hosts. Four of 

 the eight species belong to the genus Lanius, three being 

 new world and the other an old world species. Doco- 

 phorus communis occurs on them all. 



The Paridas, or titmice and chickadees, are represented 

 in the host list by eleven species, four old world and 

 seven new world. Docophorus pari is recorded from 

 three old world species of three different genera. Doco- 

 phorus rutteri occurs on two new world species of the 

 same genus and the same geographical region. Mallo- 

 phaga have been taken from three kinglets, family Regu- 

 lidae, two of them old world species and one new world. 

 Physostomum frenatum is recorded from one old world 

 and one new world host species. 



The rather large family of Mniotiltida?, or wood-war- 

 blers, is represented by twelve species, three of them 

 from the Galapagos Islands, and the others from North, 

 Central and South America. Docophorus communis is the 

 only old world Mallophagan species occurring in the 

 group, being found on three of the American host species. 



The Drepanidae, or honey creepers of the Hawaiian 

 Islands, are represented in the list by three species of 

 three different genera. Seven Mallophagan species, all 

 except one peculiar to the host group, have been taken 

 from these three hosts. One of the Mallophagan species 

 is common to all three. 



Mallophaga have been taken from five species of Alau- 

 didae, or larks, three of them old world, one new world, 

 and one inhabiting both old and new worlds. Doco- 

 phorus 



communis occurs on four of the lark species. 



