the water and begin looking for terrestrial sites to spend the latter 

 part of summer. At this time, turtles may move from one burrow site to 

 another, or may burrow into the sand and remain in one location. In 

 Iowa, Cooper (1975) observed turtles in early August, and Springer and 

 Gallaway (1979, 1980) saw their last turtle in September, thus indicating 

 to them that activity patterns may be bimodal. Indeed, terrestrial cap- 

 tures may occasionally occur throughout the summer months. Cooper (1975) 

 caught animals on land primarily between 1500-1900 h in May and 1300- 

 1600 h in June; the later in the season, the earlier the time of encounter 

 as temperatures became warmer. 



Kangas et al . (1980), monitoring 1? radio transmittered turtles in 

 Missouri, also noted that turtles moved on land, although generally near 

 water, from the time of emergence through about mid-June when they settled 

 in one location. They reported one turtle in a marsh in September, thus 

 also suggesting a second period of activity. Because of the long winter 

 hibernation and summer aestivation, the Illinois mud turtle is considered 

 fossorial , but whether it is more fossorial than other subspecies of 

 K. flavescens is unknown. Mahmoud (1969) reported a roughly similar 

 activity pattern for J<. f_. flavescens in Oklahoma although Christiansen 

 and Dunham (1972) did not observe aestivation in New Mexico. In Iowa, 

 there are roughly 106 days of annual activity, an extremely short amount 

 of time for turtles (Cooper, 1975). 



Upon emergence in spring, Illinois mud turtles spend considerable 

 amounts of time basking, occurring primarily between 1100-1500 h (Cooper, 

 1975). As the season progresses, basking becomes less frequent until 

 daily terrestrial activity takes on an early morning/evening and night 

 pattern (Kangas et al . , 1980). 



Copulation begins in May and has been observed into July; it takes 

 place both on land and in water (Kangas et al., 1980; Cooper, 1975). 

 Nesting begins in mid-June. At this time, the female completely encloses 

 herself in a subterranean nest where she lays her eggs. Smith (1961) repor- 

 ted clutches of 3-4, whereas Cooper (1977) estimated ?-6 and Kangas et al . 

 (1980) 2-8 with a mean of about four. Springer and Gallaway (1979, 1980) 

 observed two clutches, one with four eggs, the other wi1;h six, and Kangas 

 et al . (1980) found one radio transmittered female in a nest with six eggs. 

 Nests may be difficult to find. In spite of thorough searches, Christiansen 

 and Haglan (1980) found no nests in the 1980 field season at Big Sand Mound. 



While the age structures of the populations are unclear, especially 

 the subadult classes, maturity is thought to occur by the 4th year in 

 Missouri (Kangas et al . , 1980) and the 5th year in Iowa (Springer and 

 Gallaway, 1979, 1980). The sex ratio at Rose Pond, Missouri, is 1:1 

 (Kangas et al . , 1980). 



In Missouri, hatching appears to occur in early May and by June, 

 hatchlings have arrived in the ponds (Kangas et al., 1980). Generally, 



