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49 beds, particularly in the Niobrara River, though these are less common than shoreline grasses. While woody debris may be present in theses streams, I seldom find Ringed crayfish here. "Rock" in our streams usually is concrete riprap placed to protect bridge abutments, diversion dams and canal banks, and this is used when present. They are also found in the Big Blue River basin but habitats here differ from those in the more western streams. Streams here tend to be deeply entrenched. While silts, sands and gravels are the dominant substrates, rock and cobble riffles are often encountered. Measured turbidities were higher and shoreline vegetation and aquatic plants are rare. Here the Ringed crayfish is usually found in rock and cobble riffles. This characterization extends to tributaries where even the smallest riffles will harbor juveniles. On one occasion, adult Ringed crayfish were collected from a silt/sand-bed pool that had no cover whatsoever except that provided by depth and turbidity. I have not found the Ringed crayfish to burrow in Nebraska. Even in drying streams, dewatered canals, or periods of no flow, they were not found to dig burrows. Instead they were found in small cavities excavated beneath rocks or logs. The cavity is exact size and shape of the crayfish with no room to turn or move around as if they had wiggled their way under the rock. I have collected Ringed crayfish from pools in streams but have never found them in a lake or reservoir. There are three literature references to their being collected from lakes. 116, 117, 216 BEHAVIOR As is typical of crayfishes with limited ranges, there is little information on behavior. One reference noted that juveniles tended to occupy higher-velocity rocky riffles which is similar to what I have found. 80 REPRODUCTION For Ringed crayfish in southern Missouri, breeding occurs from October to April. Females were carrying eggs between late March and mid-May and the eggs were hatching by mid-May. Females in a coldwater streams were still carrying eggs and young as late as June 20 when those in other localities had no young anymore. 89, 188 In Missouri, egg counts on 18 females (41 to 79 mm), found an average of 245 eggs , ranging from 54 to 505). The bright yellow eggs were 1.6 to 2.0 mm in diameter. 188 Ringed crayfish juveniles (5-10 mm) in Kings Creek, Kansas, did not begin showing up until July and August. This was a month later than those of the Water Nymph crayfish (Orconectes nais) in the same stream. 55 In an Oklahoma stream, adults occupied backwater areas most of the year but, in the spring, egg-bearing females moved to the higher-velocity riffles. Perhaps, as a result, juveniles were more commonly found in high-velocity areas. 80