424 Mr. G. W. Kirkaldy on the 
undulata. Prof. Uhler writes that he has not seen any 
authentic examples from North America. 
This species seems to be almost confined to stagnant 
water, though I have captured a single specimen in a 
running stream. ‘his, however, appears to be unusual. 
It may be of interest to note here the colour changes 
after the final larval instar, which I have observed in two 
varieties, viz.: glauca and marginata. 
In both, the imago leaves the ultimate larval skin, 
immaculate dead-white in colour. In the course of 
development, the hemielytra become pure ivory-white, 
while the scutellum early assumes a clear pale green 
colour, the golden-yellow pubescence being then notice- 
able. In glauca, the hemielytra very gradually change 
to their normal hue, the scutellum remaining greenish 
somewhat longer. In marginata, the hemielytra pass 
through the yellowish-green stages, then becoming pale 
purplish-brown, and thence to the final bluish-black, the 
abdominis dorsum passing through very similar stages. 
The claval and corial fasciee, and the spots at the apical 
margin of the corium are ivory-white during the purplish- 
brown stage, the apical spots shortly turning yellowish 
and during the final development, the spcts become cas- 
taneous and the fascize luteous. 
17. Notonecta nigra, Fieb. 
Notonecta nigra, Fieb., 1851, Abh. béhm. Ges. Wiss. 
(5), vi., p. 473. 
I have little to say upon this species ; there appear to 
be only three specimens in collections, two in the Vienna 
Museum and one (labelled “ Type,”’ but upon which I 
can only offer an opinion similar to that on N. variabilis) 
in the collection of M. M. Noualhier. It appears struc- 
turally identical with N. glauca, and formerly, when I 
believed that N. glauca inhabited North America, it 
seemed probable that this was only a var. of that 
species. 
Long. 16 mm., lat. 5°5 mm. 
Hab. Braziu. 
I have nothing further to add to Fieber’s description. 
