THE EGGS AND LARVAE OF CRYPTOCEPHALUS QUADRUPLEX NEWMAN AND C. VENUSTUS FABRICIUS, WITH A KEY TO THE KNOWN IMMATURE STAGES OF THE NEARCTIC GENERA OF CRYPTOCEPHALINE LEAF BEETLES (COLEOPTERA: CHRYSOMELIDAE)
AbstractThe eggs and larvae of Cryptocephalus quadruplex Newman and C. venustus Fabricius are described and illustrated. Both species very likely overwinter in the larval stage. The adults emerge from the last week of May to mid-June. Before mating they feed on plants for about a week. The oviposition period is quite extended and lasts from mid-June to the end of July. The eggs are laid singly in the leaf litter. The hatching period was 10–15 days in the laboratory. The larvae develop through 5 instars and feed exclusively on dead or decaying leaves of various plants. By the end of September most of them have grown to the 4th instar, some to the 5th. At this moment they stop feeding and move deeper in the leaf litter for overwintering. The 1st instar is easily recognized by the presence of the egg bursters on meso- and metathorax, the large flattened-papillate setae of the head capsule, and the presence of 2 pairs of spiniform setae on tibiae. In the following instars the size varies as well as the number of spiniform setae on the tibiae and the number of secondary clubbed setae on the pronotum.