LANITJS ALGERIKNSIS 167 



narrow frontal line, lores, eye-region and ear-coverts jet-black ; a faint 

 indication of a white superciliary stripe ; wings black, the primaries having 

 the basal third white, and presenting a conspicuous alar patch, the secondaries 

 tipped with white, and having whitish margins to their inner webs ; edge of 

 wing white ; the four central rectrices black, the other tail-feathers black, 

 tipped with white, the amount of white increasing on each successive pair 

 as they approach the exterior feathers, the outer pair being quite white with 

 the exception of the basal half of the inner web ; underparts pale slate-grey, 

 becoming whitish on the throat, middle of abdomen and under tail-coverts. 



Iris dark-brown ; bill and feet black. 



Total length 9 inches, wing 4-25, culmen -6-5, tarsus 1'20. 



Adult female similar to the male. 



Observations. — Individuals vary amongst themselves to a certain extent. 

 Some examples show no sign whatever of any supercilium, others have it 

 fairly pronounced. The alar speculum also varies somewhat in size : as a 

 rule, however, it measures about half an inch in length, or half what it 

 usually does in L. clcgans. The proportion of black and white ou the tail 

 also varies to a certain extent in individuals. Specimens from the west of 

 North Tunisia are generally rather darker than those from the east of that 

 region. 



Two species of Grey Shrike are commonly to be met with in 

 Tunisia, one the dark-colonred L. algeriensis, Less., which occurs in 

 its typical form in that part of the Regency lying to the north of the 

 Atlas ; the other a pale form, apparently referable to L. ehgans, 

 Swains., which inhabits the country south of that range. 



Where the two species meet, however. Grey Shrikes occur, which 

 in the colour of their plumage and markings are intermediate between 

 the two. The first time I came across one of these intermediate 

 examples I imagined it to be L. fallax, Finsch, but on subsequently 

 meeting with similarly attired birds in that part of the Eegency which 

 may be considered as the meeting ground of the two species, 

 L. algeriensis and L. elegans, I was induced to alter my opinion, and 

 look upon these individuals as being either hybrids between the two 

 species mentioned above, or intermediate forms modified by local 

 causes. 



In the Ibis for 1898 (pp. 228-231) I went somewhat fully into this 

 question, and it may perhaps not be out of place for me here to give 

 the following extract of what I then wrote on the subject : — 



"As stated in my 'Notes' (Ibis, 1896, p. 94), on comparing the 



