全長1m以上(shang),尾(wei)長占全長的1/5左(zuo)右。背(bei)鱗(lin)19~19~17行,腹鱗(lin)224~231,肛鱗(lin)二(er)分,尾(wei)下鱗(lin)57~69對(dui)。眶前(qian)(qian)(qian)鱗(lin)1,眶后鱗(lin)2;顳鱗(lin)1+2;上(shang)唇鱗(lin)7,2-2-3式(shi);下唇鱗(lin)8或9,前(qian)(qian)(qian)4(3)枚切前(qian)(qian)(qian)頜片。軀尾(wei)背(bei)面(mian)呈不(bu)規則(ze)的窄橫(heng)紋(wen)(wen)(wen);頭背(bei)斑(ban)紋(wen)(wen)(wen)的典型特征是(shi):前(qian)(qian)(qian)端有(you)(you)兩條黑(hei)橫(heng)紋(wen)(wen)(wen),一(yi)橫(heng)跨吻背(bei),一(yi)橫(heng)跨兩眼間(jian),在眼下伸達(da)唇緣,眼后另有(you)(you)一(yi)短黑(hei)紋(wen)(wen)(wen)斜達(da)口(kou)角;頭頂部(bu)有(you)(you)2~3個尖端向(xiang)前(qian)(qian)(qian),彼此套(tao)迭(die)的倒"V"字形黑(hei)紋(wen)(wen)(wen)。以上(shang)鱗(lin)被(bei)及斑(ban)紋(wen)(wen)(wen)等與(yu)我國錦(jin)蛇(she)屬其它(ta)種相區別(bie)。
生活于海拔2000~2500m,濕潤山(shan)地落葉(xie)闊(kuo)葉(xie)林下(xia)(xia)或農耕(geng)地周(zhou)圍的草、灌叢(cong)(cong)中(zhong)。80-1號雌性系5月(yue)上旬在汶川縣(xian)(xian)平坦(tan)河谷的農耕(geng)地邊草、灌叢(cong)(cong)中(zhong)爬行采(cai)到(dao)(dao);88-3號雌性系6月(yue)初在瀘定(ding)縣(xian)(xian)于暴雨前夕在落葉(xie)闊(kuo)葉(xie)林下(xia)(xia)人行道(dao)旁爬行被采(cai)到(dao)(dao);87-2號雄性系10月(yue)下(xia)(xia)旬在瀘定(ding)縣(xian)(xian)叢(cong)(cong)林下(xia)(xia)流(liu)溪旁石(shi)堆中(zhong)翻出。
中國(guo)特有種(zhong)。目前僅知分布于(yu)四川西部雅安、汶川及瀘定山區(qu)。
橫(heng)斑錦(jin)(jin)蛇自在雅安采得一(yi)雄性(xing)標(biao)本于(yu)(yu)1929年訂(ding)名以(yi)(yi)來(lai)(lai),在以(yi)(yi)后的半個世紀(ji)里(li)均未再被發現,于(yu)(yu)是有人開始懷疑其(qi)種(zhong)(zhong)的真實性(xing)。直到20世紀(ji)80年代,鄧其(qi)祥等才又于(yu)(yu)四川(chuan)(chuan)省汶(wen)川(chuan)(chuan)縣臥龍自然保護區及(ji)瀘定(ding)縣海(hai)螺溝森林冰川(chuan)(chuan)公園采得3號標(biao)本。趙爾宓還為此專門(men)撰文論述了橫(heng)斑錦(jin)(jin)蛇種(zhong)(zhong)的有效性(xing)。橫(heng)斑錦(jin)(jin)蛇共見于(yu)(yu)汶(wen)川(chuan)(chuan)、寶(bao)興、瀘定(ding)、雅安及(ji)石棉5個縣市。另(ling)外,從分布型來(lai)(lai)看,橫(heng)斑錦(jin)(jin)蛇屬于(yu)(yu)橫(heng)斷山型,并(bing)且為分布極不廣泛的土著種(zhong)(zhong)。