Giant African Snail — LANGE 
333 
lighter, receded into the shells, then became 
black, and finally a watery, dark-colored li- 
quid exuded from the apertures. From dying 
and dead snails two species of sarcophagids 
were reared, namely, Sarcopbaga gressitti 
Hall and Bohart and S. dux Thomsen -(de- 
termined by C, W. Sabrosky). These flies 
were apparently saprophagous, being at- 
tracted to dying snails. Hall and Bohart 
( 1948: 132 ) report Sarcopbaga gressitti from 
Saipan, Tinian, and Rota, where it was asso- 
ciated chiefly with filth, dead fish, dead land 
crabs, and snails. 
During these observations there was no 
evidence of an epizootic among snails; rather 
it appeared that dying snails were stranded 
on roads and runways and partially desic- 
cated before they could obtain adequate 
cover. This does not, however, preclude the 
possibility of a pathological condition among 
snails in other areas or under other conditions. 
The presence of thin and consequently 
fragile shells among snails on Saipan, Tinian, 
and Rota did not seem associated with a 
pathological condition. The possibility of 
genetic factors is indicated in certain Saipan 
localities where normal thick-shelled indi- 
viduals occurred in association with thin- 
shelled snails. In certain cases, as on Rota 
(Fig. 9), the bleached shells of dead snails 
were found in large numbers. The reason 
for the death of these snails could not be 
determined. 
CONTROL 
The control of the giant African snail on 
Saipan has been approached in three ways: 
By chemical control, cultural control, and 
biological control. In certain cases it was 
possible to protect crops by the frequent use 
of pelleted baits containing metaldehyde and 
calcium arsenate. In areas separated from 
dense growth the use of a peripheral weekly 
treatment with pellets was found to give sat- 
FlG. 9- Bleached shells of dead Achatina on Rota airstrip, March 16, 1948. 
