An. das Mem. do Instituto de Butantan — Vol. 1 - fasc. 1 (Ofiologia) 19 
The principal differences between L. jararaca (WIED) and 
L. atroax (L.) are found in their coloration, in the shape of the blotches 
on the back and in the upper labials which in the last mentioned 
are generally Y7, whereas in the first mentioned they are ge- 
nerally 8. VITAL BRAZIL assigned 7/7 to the L. atrox (L.), and 
J. FLORÊNCIO GOMES (27) in 5 perfect specimens and 100 heads 
of L. atrox (L.), from the State of Pará, verified that, among 
the perfect, 5 and, among the heads, 95 (28) had 7/7 upper labials, 
2 had 8/8 and 3 had 8/7. 
On examining the above mentioned 228 specimens of L. atrox 
I found 7/7 upper labials in 215; 8/7 im 11; and 8/8 in 2. 
| On the other hand, in the above numerated 4.358 specimens 
of L. jararaca (WiED) I verified that 3.710 had 8/8 upper labials; 
346 had 7/8; 180 had 9/8; 108 had 8/9; and 9 had 9/9. 
Beside there is data of the zoôgeographic order which seems 
to me to be highly valuable in the distinction of the species. 
Lachesis jararaca, in efect, occurs only in the Meridional 
hemisphere and its presenca in Brazil has up to now only been 
verified approximately between parallel 30º S. (State of Rio Grande 
do Sul) and parallel 10º S. (State of Baía). 
Lachesis atrox (L.), on the contrary, is found in both hemis- 
pheres, Septentrional and Meridional, and in Brazil the area of 
its distribuitioo extends from N.W. of the State of São Paulo 
avd S. of the State of Mato Grosso, in the proximities of parallel 
23º S., to the extreme Septentrional region of the country, beyond 
the Equator. 
This data concerning the distribuition of the two species in 
Brazil was taken from the register in the Butantan Institute, 
which has since its foundation always recejved an ever increasing 
number of these snakes' which were disposed as follows during 
the last 6 years: 
Total number of 
Venemous 
NEAR | snakes received species. 
1915 | 5.025 3.568 
1916 4.832 31535 
1917 6.133 3.833 
1918 6.416 4.078 
1919 1.162 5.815 
1920 11.400 8.370 
Having thus established the identification of the two important 
Crotalinea which occur in Brazil, the «Jararaca» with L. ja- 
raraca (WIED) and the «Caiçaca» with L. atrow (L.), I shall 
(27) J. FLorêncio Gomes — pa io para o conhecimento dos ofídios do Brazil. [IT — Ofídios 
do Museu Paraense”, im loc. cit.; p. 
(28) Through a mistake 85 SR of 95 figures im this work. The latter is according to A.'s original, 
