Several considerations are involved in human health, The in- 
halation of guano and chitinous dust which floats in the air can 
cause irritation. Recent findings by Emmons (1958) show that the 
fungus, Histoplasma capsulatum, causal agent of pulmonary histoplas-— 
mosis, has been associated with house bats in the U.S.A. and isolates 
have already been taken from various bat habitats in Trinidad. The 
rabies virus has been isolated from Molossus major, the most abundant 
species found in houses. Greenhall (1959) collected it in a house 
in Trinidad. Although only a few species of mites (Dermanyssidae and 
Myobiidae), dipteran bat flies (Streblidae) and hemipteran bugs 
(Polyctenidae) have been recorded as ectoparasites on the species of 
house bats mentioned below (Anon. 1958), attention is drawn to their 
possible health hazard by Scott (1958): "Bat Ectoparasites (ticks, 
mites and fleas) may attack man, particularly when bats are infesting 
a house," 
DISTRIBUTION OF FREE-TAILED BATS (MOLOSSIDAE) 
The Molossidae or free-tailed bats, all of which are insectivo- 
rous, occur in the tropical and subtropical regions of both hemispheres, 
with intrusions of two genera, Tadarida and Eumops, into the Southern 
United States. 
Approximately a dozen genera of this family have been described 
with only five normally occurring in the Western Hemisphere, Four of 
these have so far been found in Trinidad: Tadarida, Molossops (Cynomops), 
Promops and Molossus. The first three, up to now, have not been observed 
roosting in buildings, but have been taken under leaves and in hollow 
tree branches, Members of the genus Molossus are usually found in build- 
ings, though they are occasionally taken under palm leaves and in hollow 
trees. The reasons for this variation of habitat are not clear, as con- 
ditions under an enclosed, hot, galvanized iron roof are certainly very 
different from those found under an open palm leaf or in a hollow tree 
trunk, Nevertheless, it is man who has created the enticing artificial 
conditions for the bats and more often than not laymen disregard the 
beneficial contributions the bats make. 
SPECIES AND ABUNDANCE OF MOLOSSUS 
Only two species of bats were encountered in these experiments 
and both belong to the genus Molossus. The commonest species was the 
little free-tailed bat, Molossus major (Kerr), with 1,592 collected 
dead, This is also the most abundant species of bat frequenting roof 
spaces in Trinidad, The other species present was the greater free- 
tailed bat, Molossus rufus Geoffroy, with 339 collected. 

