Impaction of the rumen in cattle due to the ingestion of the cocoons of the Molopo caterpillar Gonometa postica (Walker).

Fig. 1 Gonometa postica: Moth, opened and entire cocoon. from rumen impaction in the North-Western Cape. Similar losses, reported by Edwards I from the Northern Transvaal in 1935, were caused by cocoons of the moth Gonometa rufubrennea. A related moth of the same genus, Gonometa postica (Walker) (fig. 1) occurs in the North-Western Cape, namely north of an imaginary line drawn from Mafeking to Vryburg, Kuruman, Upington and Karasburg, and in the southern parts of Bo~swana and South West Africa. The caterpi liars of the G. postica appear shortly after the first summer rains. They live on thorn trees, especially on the black thorn and the camel thorn. The cocoons, five by two cm in size, are light grey in colour and covered with tiny, short, black spicules (fig. 1). This specific study was conducted in the Vryburg and Mo!opo areas, as result of reports of extensive mortality.