An introduction to the biology of craneflies in a series of abandoned beaver ponds, with an account of the life cycle of Tipula sacra Alexander (Diptera; Tipulidae)
A series of five beaver ponds that have been abandoned for about 10 years is described, and an introduction to the ecology of the area is given. The life cycle of the cranefly Tipula sacra is described. This is the commonest cranefly in the area and the larvae are important grazers on the microflora in benthic sediments. There are four larval instars, which can be separated by a combination of the presence or absence of setae on the spiracular lobes and the size of the spiracles. Larvae in instars III and IV can be sexed by examination of the gonads, while the presence of growth lamellae on the lateral sclerites of the head capsule shows promise as a means of aging larvae in all instars.