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t t t a i t 1 i Organisms associated with P_lag_opte_rus, other than fishes, are a few invertebrates such as burrowing dragonfly naids (Gomphidae), burrowing chironomid dipterans and, where stones or other solid substrates occur, simuliid dipterans, hydropsyctlid trichopterans, and a few mayfly nymphs (usually baetids). FOOD HABITS P. argentissimus possesses a stomach that is not well defined, occupying about 20X of the total gut length. Examination of 14 specimens collected by Cross in August, 1974, produced the following food items: amorphous material (presumably organic) and sand grains were most abundant, insects were commonly found (aquatic insect larvae, especially diptera, were predominant; ants and other terrestrial insects were rare); filamentous algae and organic detritus occurred in about one-half of the individuals; amphipod larvae were found in two specimens. Lockhart (1979) examined 188 woundfin from all seasons of the year and osberved that they were quite unselective in their food habits. Filamentous algae (Zygnemataceae) was the dominant items in specimens he examined. Winget and Baumann (1977) examined 16 woundfin from two collection periods and found insects the most common food item, especially diptera and stonefly larva. Cope and Yarrow (1875) stated that the dentition and intestines of the Plagopterines suggested carnivorous habits. The intestine length/ standard length ratio for P. arg~entissimus is slightly less than unity placing it near the division between Odum's (1970) carnivorous (less than one) and omnivorous (1 to 3) species. Considering the relative length of the gut, it would seem that algae and organic detritus would not provide much food value. It may be that bacteria, protozoans and micro-algae attached to large algae and detrital particles supply the nutrients or aid in the breakdown of plant material. In laboratory aquaria (39 and 208 liters) woundfin at first showed no evidence for visual selection of food. Soon after dried foods were introduced into the aquaria, woundfin began milling excitedly about the bottom. For a few weeks they fed on or just above the bottom. Within one month most individuals had begun rising to the surface to feed (Cross, 1975). REPRODUCTION Little is known of the reproductive biology of woundfin. Peters (1970) gives some information, and Cross (1975) and Deacon (1977) make some general observations. However, the stimulus which initiates the repro- ductive cycle has not been determined, spawning habitat and substrate are not known nor have thorough observations on reproductive behavior been made. Initiation of the reproductive cycle may be related to rising water 7