A total of 443 bat flies belonging to the families Nycteribiidae and Strelidae, were collected on 22 species of bats (Molossidae, Phyllostomidae, and Vespertilionidae) from Parque Estadual da Cantareira (São Paulo, Brazil), between January, 2000 and January, 2001. Eighteen new occurrences of bat flies were recorded on
Anoura geoffroyi
(
Anastrebla caudiferae
),
Glossophaga soricina
(
A. caudiferae),
Sturnira lilium
(
Trichobius phyllostomae
,
T. furmani, and
Paraeuctenodes similis
),
Artibeus lituratus
(
A. caudiferae),
A. fimbriatus (
Megistopoda proxima
),
A. obscurus (
Metelasmus pseudopterus
),
Myotis nigricans
(
M. proxima,
M. aranea,
Paratrichobius longicrus
),
M. ruber (
Anatrichobius passosi
,
Joblingia
sp.),
M. levis (
A. passosi),
M. albescens (
A. passosi,
Basilia andersoni
), and
Histiotus velatus
(
M. aranea). Seven new occurrences were recorded for the state of São Paulo, increasing the range for
T. tiptoni,
T. furmani,
M. proxima,
Aspidoptera falcata
,
A. caudiferae,
A. modestini and
B. andersoni. The relationships between parasitism and host sex, reproductive stage, age hyperparasitism by fungi are discussed.
