. Bulletin of the Department of Agriculture. Agriculture; Agriculture. BULLETIN" 1218, U. S. DEPARTMENT OF AGRICULTURE. When the larvae were in the prepupal stage or had already pupated no more water was added and the media usually became quite dry before the adults emerged. It was found that the adults would soon denude themselves if left more than an hour or so in the rearing jars. Tabanid eggs collected in the field hatched very readily in the laboratory, but it was found that the. period of incubation was con- siderably shorter in cases where they were exposed to high tempera- tu
. Bulletin of the Department of Agriculture. Agriculture; Agriculture. BULLETIN" 1218, U. S. DEPARTMENT OF AGRICULTURE. When the larvae were in the prepupal stage or had already pupated no more water was added and the media usually became quite dry before the adults emerged. It was found that the adults would soon denude themselves if left more than an hour or so in the rearing jars. Tabanid eggs collected in the field hatched very readily in the laboratory, but it was found that the. period of incubation was con- siderably shorter in cases where they were exposed to high tempera- tures in direct sunlight. The eggs were taken to the laboratory on a portion of the vegetation or object to which the mass adhered and suspended over about a half inch of water in a glass vial an inch in diameter. A cotton stop- per was placed in the vial to pre- vent any intrusion of predators or escape of emerging parasites. Upon hatching, the larva? dropped to the water. Tabanus punctifer larvae would remain near the sur- face; T. phaenops larvae would remain more deeply submerged. The number of eggs was deter- mined in most cases by counting the larvae. In the case of badly parasitized egg masses the egg- shells had to be counted. Egg masses of T. phaenops often be- came detached and dropped into the water, where they failed to hatch. This can be avoided largely by leaning the vials at an angle. Larvae collected in the field were placed with mud in vials or jars, several being in one container, and were carried to the laboratory with very little fatality. OVIPOSITION CAGES. It has been found very difficult to get Tabanus punctifer and T. phaenops to bite a host in captivity. A screen-wire cage 5 feet high and 10 feet square was constructed partly over water near a sluggish stream. The cage contained water plants and other vege- tation upon which it was hoped the flies might oviposit. A calf 1 months old was placed in the cage September 1, 1917. About 300 flies (T. phaenops),
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