The survival and pupation rates of late-stage larvae of 2 wireworm species,Melanotus depressus(Melsheimer) andLimonius dubitansLeConte, maintained on one of 4 soil substrates or on soil and germinating wheat were studied. AllM. depressuslarvae held for 21 mo on soil and germinating wheat underwent 2 or 3 larval ecdyses. Pupation occurred in May and June of the 1st year and March through May of the 2nd year. Dormancy occurred during the winter months. In the absence of germinating wheat, larvae showed a tendency towards retrogressive ecdyses. Although mortality was high,L. dubitanslarvae held under the same conditions for a period of ca. 11 mo appeared to show similar biological cycles. Larval ecdyses were observed 2 or 3 times and dormancy occurred during the winter months. No ecdyses were observed from December to February.L. dubitanslarvae, unlike those ofM. depressus, did not undergo regressive ecdyses and died from starvation within 6 mo.