NO. 3655 PARALLEL EVOLUTION—FRIEDMANN 3 
been able to study in depth the morphology and distribution of the 
smaller Indicator species. Some of the specimens were collected under 
National Science Foundation Grant GB-5107. 
The exilis-willcocksi Relationship 
The small west African forest honey-guides, erilis and willcocksi, 
were considered conspecific prior to Chapin’s 1962 study when, for 
the first time, the specific identity of the latter sibling form was 
elucidated. Until then willcocksi had been treated as a western race 
(Ghana and Togoland) of ezilis; the fact that willcocksi-like indi- 
viduals occurred here and there throughout the range of nominate 
exilis was, if anything, looked upon as evidence that the latter race 
provided the variational trends that had become “‘solidified”’ in will- 
cockst. 
A good number of specimens of willcocksi collected in 1966 and 1967, 
along with those of ezilis (pachyrhynchus) in extreme western Uganda 
(Kibale and Impenetrable Forests), clearly upholds Chapin’s con- 
clusions in regard to the distinctness of the two sympatric species. 
When series are laid out, the differences between the species is more 
marked than that suggested by single examples. 
Chapin’s attention was brought to bear on the ezilis-willcockst 
situation as a result of his discovery and description of the still smaller, 
partly sympatric pumilio. While the validity of pumilio as a species 
distinct from its sympatric congeners is clear as has been universally 
accepted by all students of African birds, Chapin (1958, p. 47) did 
not pursue the question of its relation to the paler, small Indicator 
species of the open country of eastern Africa beyond commenting 
that the very small beak of pumilio caused him to think at first that 
it might be conspecific with meliphilus. The striking difference in 
coloration of the two species persuaded him to name pumilio bi- 
nomially, but he felt constrained to add that he was still of the opinion 
that “its small beak may well indicate relationship with mel- 
apis? 
The meliphilus-narokensis Relationship 
Just as willcocksi had been looked upon as a part of the variational 
limits of ezilis until sufficient series of specimens became available 
for study, meliphilus too has been assumed to comprise within its 
extremes, the species appelator Vincent (1933) and narokensis Jackson 
(1906). Ever since Chapin’s discovery of pumilio in the Kivu forests 
I have wondered whether or not meliphilus, like willcocksi, might 
also have a smaller, sympatric sibling form. The description and 
dimensions of appelator, described from Zobué on the border of 
Mozambique and Malawi, were too close to those of meliphilus to 
