92 Charles R. Blem and Leann B. Blem 



females: t = 22.4). and smaller but significant differences occur between 

 subcaudal counts (males: t = 2.3; females: t = 8.9). It appears that signifi- 

 cant geographic variation occurs in scale number of V. striatula, 

 although the pattern is not clear. Mount (1975) gave subcaudal counts 

 for Alabama striatula that are lower than those of Virginia or Texas 

 specimens (males: 38.5; females: 34.2). Mean ventral counts of Alabama 

 males (121.2) are intermediate between those from Virginia and Texas, 

 while ventral counts from females (124.8) are lower than those of the 

 other states. 



Although our collecting efforts were not evenly divided over all 

 months, it is obvious that earth snakes were more available in March, 

 April and May (63/102 = 61.8% were collected in these months). This 

 may be due to increased exposure as a result of mating activity. Clark 

 (1964) concluded that mating of V. striatula occurred in Texas during 

 March and April, as judged from the presence of spermatozoa in the 

 lumina of the oviducts. D. Greene (pers. comm.) observed copulation in 

 a group of 30 or more individuals accidentally excavated from a hiber- 

 naculum at Richmond, Virginia, on 30 March 1982. This suggests that 

 first mating may occur shortly after emergence from the hibernaculae in 

 early spring. 



Size distribution of V. striatula in central Virginia seems skewed 

 toward larger snakes. For example, males of striatula as small as 123 

 mm snout-vent length were collected in May, yet only 28.0% (7.25; 

 newborn young excluded) of the entire sample was less than 164 mm 

 (minimum size at maturity). For females, 123 mm also was a minimum 

 size of May specimens, yet only 33.0% did not exceed 175 mm. This bias 

 toward large size indicates either that subadult earth snakes are difficult 

 to find, or that mortality rates of young are relatively great. We believe 

 that the latter hypothesis is correct. Subadult snakes do not seem to 

 behave differently from older snakes, as they often were found with 

 adults or in similar sites. Also, the abundance of small V. valeriae sup- 

 ports this contention. About 41.7% (5/12; newborns excluded) of male 

 V. valeriae and 57.1% (8/14) of female valeriae were shorter than 

 mature individuals. Virginia valeriae is not at the northern edge of its 

 range as is V. striatula at this collection site. We hypothesize that mid- 

 winter mortality of young snakes may be important, as it is in the east- 

 ern cottonmouths, Agkistrodon p. piscivorus that also reach the 

 northern edge of their range in this area (Blem 1981). 



Gravid female V. striatula near the northern edge of the range are 

 smaller than those reported by Clark (1964) and by Clark and Fleet 

 (1976) in Texas (Table 1). Since error terms are not available for the 

 Texas sample, statistical comparison is not possible. Clark and Fleet 

 demonstrated a significant regression of litter size on snout-vent length 



