Walter Tschinkel, a Florida State University entomology professor, has been making plaster casts of ant nests since 1982, when he first heard of the strength of orthodontic plaster. The painstaking process involves pouring the plaster down the opening as quickly as it will go in. After the plaster hardens, the excavation begins, but the nest must be taken out piece by piece. (One harvester ant nest, for example, took some five gallons of plaster and came out in 180 pieces.) Sometimes more than ten feet tall, the nests are as beautiful in structure as they are complex.