1915.} Allen, Review of the South American Sciuride. 2h 
been collected, although it seems impossible to separate subspecifically 
central Costa Rica specimens from those of the Western Andes in Colombia. 
A second group (subgenus Histriosciurus !) is the gerrardi group, con- 
sisting of a considerable number of exceedingly variable forms (1 species 
with 7 subspecies) the most diverse of which, in their extreme phases, are 
strikingly unlike in coloration, and vary inter se to some extent in size and 
cranial characters. In proportions of parts and in cranial characters they 
are quite similar to the hoffmann section of the genus. The gerrard: forms 
are practically restricted to the tropical zone, and occupy the low lands of 
northern and western Colombia from the Venezuela boundary to the Canal 
Zone in Panama, and range thence southward along the coast of Colombia 
to northeastern Ecuador. So far as now known the ranges of the gerrardi 
and hoffmanni groups do not overlap. 
The third group (subgenerically referable to Histrioscvwrus) consists 
of 2 species and 2 subspecies, the saliuensis group of the Santa Marta dis- 
trict of northeastern Colombia and pyrrhinus of Peru. The known forms 
of this group are similar in size to the forms of the gerrardi group, but do 
not closely resemble them in coloration, but in other respects are nearly 
related. The saltwensis group is white-bellied, while the gerrardz group 1s 
red-bellied. Although not formerly known to occur outside of the Santa 
Marta district, it has recently been found to reach the lower Cauca valley, 
while an allied form (Sciurus pyrrhinus Thomas) is known from Peru. 
This may be either white-bellied or red-bellied, at the same localities. 
List of Species and Subspecies, with their type localities, and statement of 
number of specimens examened. 
Mesosciurus hoffmanni hoffmanni (Peters). “Costa Rica”; here desig- 
nated as San José, Costa Rica. Specimens examined, 87. 
Mesosciurus hoffmanni chiriquensis (Bangs). Divala, Chiriqui, Panama. 
Specimens examined, 90. 
Mesosciurus hoffmanni manavi (Allen). Manavi, Rio de Oro, Ecuador. 
Specimens examined, 12. 
Mesosciurus hoffmanni quindianus (Allen). Rio Frio, Central Andes, 
Colombia. Specimens examined, 15. 
Mesosciurus hoffmanni hyporrhodus (Gray). Santa Fé de Bogota, 
Colombia. Specimens examined, 28. 
Mesosciurus griseogena griseogena (Gray). “ Venezuela” (apud Thomas). 
Specimens examined, 39. 
1'Type, Sciurus gerrardi Gray. 
