Locusts as Propagators of Foot and Mouth Disease 85 
systematic and more general storage of ensilage and other winter 
forage for stock. 
What makes the matter more serious is that, if what I am trying 
to establish is a fact, the locusts are a double source of danger ; 
they act in the first place as infection-carriers, and then, by devouring 
the herbage, they deprive our ruminants of their only chance of over- 
coming the disease. 
Our farmers associate locusts and foot and mouth disease. They 
hold, with how much truth I cannot say, that the disease is epidemic 
when locusts are abundant. This much is certain: the end of the last 
visitation of locusts dates back about twenty years; during the interval 
foot and mouth disease was unknown. 
Whilst on the subject of locusts, I may mention, as perhaps of some 
interest, that twenty years ago the number of swarms steadily decreased 
before they entirely disappeared, and it was universally held here by 
our farmers that the cause of extinction was the parasitic ‘ worm.’ 
The later swarms were all found to be thus infected. I have no doubt 
in my own mind that this is the correct explanation. The swarms 
died before they could lay their eggs. The same thing is happening 
now, and upon this fact I base a hopeful augury for the future. About 
three months ago I examined a number of locusts from a swarm 
passing over the village ; two-thirds had each from two to three larvee 
flourishing in their vitals. Nature is thus efficiently aiding us. Shall 
we assist Nature ? 
In 1832, or thereabouts, in addition to the chronic visitation of 
the ordinary kind an immense swarm of a different species ap- 
peared. They were much larger, redder, and more robust on the 
wing. At first they kept apart, but eventually got scattered by and 
intermixed with the ordinary kind, from which they could easily be 
distinguished on the wing on account of their greater size. ‘They 
looked like little birds flying in company with the locusts,’ are the 
words of one of my informants. They settled principally on trees, 
which they stripped of their leaves. It was the beginning of the fruit 
season, and they devoured green and ripe fruit indiscriminately. They 
had not been seen before nor since. Could this have been an invasion 
from Northern Africa of Acridium peregrinum ? 
