1916. | F F. Lariaw: Indian Odonata. 135 
lamella there is a similar row of equal extent on both sides of the 
mid-rib. 
Lastly, on the ventral margin of the outer pair, and on the 
dorsal margin of the central lamella there lies another row of teeth 
also extending from the base for about two-fifths of the total 
length of the lamella. 
Subfamily GOMPHINAE, Rambutr. 
Genus Davidius, Selys. 
Davidius aberrans (Selys). 
Hagenius (7?) aberrans, Selys, Bull. Acad. Belg., (2) XXXVI, p. 506 
(1873); Kirby, Cat. Odonata, p. 75. 
Davidius ? zallorensis, Selys, l.c., (2) XLVI, p. 667 (1878); Kirby, J.c,, 
P- 75: 
Davidius aberrans, D. zallorvensis, Williamson, Proc. U. S. Nat. Mus., 
XXXIII, 1907, pp. 286-287. 
See also Selys, Ann. de la Soc. Entom. de Belgique, XXXVIII, 1894, 
ps i755: 
1@. Binyar, Kumaon, 7700 ft., 24-v-1g12 (A. D. Imms) 
For. Zool. Mus. 
I have compared this specimen with the descriptions of 
D. aberrans and of D. zaliorensis and can find no grounds for sepa- 
rating the two species. In the specimen before me the triangle 
of the left fore-wing is free, that of the right is crossed by a single 
nerve. Both hind-wings have the triangle crossed. 
Davidius davidi, Selys, subsp. assamensis, nov. 
Davidius davidi1, Selys, Bull. Acad. Belg., (2) XLVI, 1878, p. 671. 
I@7,2? 2%. Gopal, Assam, 1914 (H. Stevens). 
Length of abdomen @ 31 mm.,2 28 mm. 
. hind-wing ” 26 mm.,? 28°5 mm. 
Distinguished from the type by its smaller size (D. davidi type: 
abdomen ? 34°35 mm., hind-wing 32°33 mm. Selys, Joc. cit.), and 
absence of isolated superior antehumeral spots of cuneiform shape 
which occur in the type. The basal black band on the frons is not 
large. 
The male differs from the female so far as colouring goes 
chiefly in having only the lower third of the mid-dorsal carina of 
the thorax coloured, and in having lateral spots on the first three 
seginents only of the abdomen. 
Anal appendages of male: Upper pair slender and rather 
horn-like, each with a stout downwardly curved, rounded, hook- 
like process projecting from near its base, scarcely visible in profile. 
The appendage itself is longer than the tenth segment. The lower 
appendage is shorter than the upper pair, triangular and deeply 
cleft in the middie tine (see fig. 2a). 
The male has the triangle of the left hind-wing crossed, the 
remaining triangle free. 
