. Bulletin. Natural history; Natural history. November, 1961 Smith: Amphibians and Reptiles of Illinois 197. Fig. 188.—An adult Coluber constrictor flavivcntris X priapus intergrade from Union County, Illinois. The color above may be blue-green, blue-black, or slaty black; below, yellowish white, pale gray, or slate color. indistinct posteriorly, venter with brown markings; each hemipenis with large basal spines. Variation.—Specimens of this species can be reliably sexed only by determining the presence or absence of hemipenes. The mean difference between the male and the female in number of c
. Bulletin. Natural history; Natural history. November, 1961 Smith: Amphibians and Reptiles of Illinois 197. Fig. 188.—An adult Coluber constrictor flavivcntris X priapus intergrade from Union County, Illinois. The color above may be blue-green, blue-black, or slaty black; below, yellowish white, pale gray, or slate color. indistinct posteriorly, venter with brown markings; each hemipenis with large basal spines. Variation.—Specimens of this species can be reliably sexed only by determining the presence or absence of hemipenes. The mean difference between the male and the female in number of caudals and ventrals consists of only 3 or 4 scales. The juvenile is strikingly different from the adult, possessing reddish dorsal blotches that become progressively more closely crowded and more indistinct posteriorly. The tail is usually brownish gray, the venter speckled with brown, and the side of the head spotted with white. Individuals 500 mm. or more in length usually retain the blotches only on the anterior portion of the body. The ventral spotting usually persists in specimens 700-800 mm. in length, al- though these snakes are unicolorous above. The proportion of tail length to total length does not vary ontogenetically. Adult racers in extreme southern Illinois are usually blue-black above and slate color below, except for their conspicuously white chins, the edges of which are occasionally flecked with black. Occasional individuals ] Table 57.—Geographic variation from north to south in Illinois Coluber constrictor. Fig- , ures in parentheses are numbers of specimens. Characteristic Extreme Northern Illinois (15) Range Mean West- Central Illinois (15) Range Mean East- Central Illinois (15) Range Mean Lower Mississippi Border (15) Range Mean Extreme Southern Illinois (25) Range Mean Ventrals Caudals Tail length as 172-182 71-87 170-187 76-89 168-186 76-96 170-184 82-95 173-189 84-97 percentage ot total lengt
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Keywords: ., booka, bookcentury1900, bookdecade1910, booksubjectnaturalhistory
