1929 ] The Biology of Two Cixiid Plant-Hoppers 289 
two sides of the same insect. The pores are connected, in a 
fore and aft direction, with their fellows before and behind 
or with the posterior and anterior edge of the plate. These 
lines, which are apparently fine grooves, are smooth and 
shining, as also are the pores themselves ; but the wax-plate 
surface is dull dead white, due to a minute hexagonal 
sculpturing like that of many insect choria. 
Towards the end of an instar the abdomen lengthens 
greatly (fig. 1.) At other times the abdomen is shortened 
and turned slightly upward, so that the three pairs of 
wax-plates occupy by far the greater part of the dorsal 
aspect of the abdomen, the tergites of segments I-V being 
squeezed considerably. 
Curiously enough, while the penultimate instar hind 
wing-pad (fig. 5) has 3 large circular sensoria near its 
apex, the last instar has only one, which just misses being 
covered by the growing tegminal pad. The other two, 
which would be covered and thus presumably unable to 
function, have become obsolete. 
Bothriocera signoreti Stal, 1864. 
Myers: loc. cit. p. 15. 
The striking, dark brown-marked adults of this species, 
with a curiously squarely-expanded head were swept during 
March, when the dry season was at its height from vegeta- 
tion of various types, but nearly always in close proximity 
to water. Thus it occurred on flowering heads of papyrus 
in the Botanical Garden, on Commelina nudiflora , on two 
species of ferns growing in moist but not shaded situations, 
almost plentifully on pure stands of Polygonum acre along 
a nearly dry ditch and finally from a tangle of bushes, 
trees and lianes in a creek-bed. 
The tegmina, in life, are held perfectly flat, like those of 
certain small moths, which these hoppers resemble also in 
general appearance. 
Two adults were taken under stones in a nearly dry 
creek-bed of a patch of rocky forest near the laboratory. 
Here also the nymphs described below lived in a truly re- 
markable association. Under the same stones occurred large 
