. Bulletin. Natural history; Natural history. November, 1961 Smith: Amphibians and Reptiles of Illinois 225 medially, becoming white laterally and an- teriorly. Variation.âThe male northern flat- headed snake has fewer ventrals, more cau- dals, and a proportionately longer tail than the female. The juvenile tends to have a darker and more conspicuous head cap than the adult. Only 13 specimens of this snake have been found in Illinois. Eleven are available for study. Four males from Union County vary as follows: ventrals 121 to 124 (average 123), caudals 49 to 51 (average ), tail length 21.
. Bulletin. Natural history; Natural history. November, 1961 Smith: Amphibians and Reptiles of Illinois 225 medially, becoming white laterally and an- teriorly. Variation.âThe male northern flat- headed snake has fewer ventrals, more cau- dals, and a proportionately longer tail than the female. The juvenile tends to have a darker and more conspicuous head cap than the adult. Only 13 specimens of this snake have been found in Illinois. Eleven are available for study. Four males from Union County vary as follows: ventrals 121 to 124 (average 123), caudals 49 to 51 (average ), tail length to (average ) per cent of total length. Four females from the same locality have characters as follows: ventrals 125 to 132 (average ), caudals 42 to 47 (average ), tail length to (average ) per cent of total Fig. 213.âDistribution of Tantilla gracilis. Hatching indicates the presumed range of the subspecies halloivelli in Illinois; solid circles indicate localities represented by specimens examined during this study; the open circle indicates a locality represented by a published record believed to be valid. The lower map â depicts the total range of the species in the United States. Three females from Monroe County vary as follows: ventrals 129 to 132 (average ), caudals 44 to 45, tail length to (average ) per cent of total length. Scale rows are 15 in all 11 snakes; supra- labials are 5 -f 6 in one, 6 -f 6 in seven, 6 -t- 7 in two, 7 + 7 in one; inf ralabials are 6 -f- 6 in nine, 6+7 in one, and 6 + 5 in one; preoculars are 1 + 1 in nine, post- oculars 1 + 1 in eight, 2 + 2 in one, and oculars undeterminable in two. Habits.âThe northern flat-headed snake, the smallest Illinois snake, is strictly fos- sorial. Specimens are usually found by rais- ing flat rocks in dry talus slides. Although these tiny snakes possess minute poison glands and rear fangs, they are too small to bite man. Their food consists of small
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