1909. | LIFE-HISTORY OF THE AGRIONID DRAGONFLY. 265 
segments of the antenne. In the labium the labial palpi now 
each bear 3 hairs, the new ones having been added below the 
second. A second pair of hairs has also appeared on the body of 
the labium between the other two hairs. These new hairs may 
be as large as the first pair or they may be smaller, only attaining 
full size at the next moult. In later stages the new hairs always 
appear aS minute spines and are often only half their full size 
after the following moult, although they are more usually full 
size by that time. 
A marked increase in the extent of the circulation is now 
visible. ‘The corpuscles can be seen passing up the inner side of 
the first, second, and part of the third antennal segments. About 
halfway up the latter segment they cross over to the outside of 
the antenna and return to the head. Circulation is also distinctly 
visible in the bases of the legs as far as the trochanters, passing 
out from the body anteriorly and back to the body along the 
posterior side and beneath the tracheal tube. 
In the femora an irregular movement of blood-corpuscles is 
recognizable, but very few seem to be present and these are con- 
stantly being temporarily held up among the muscle-fibres. 
Usually, in this stage, small ridges appear on either side of the 
second and third thoracic segments, this being the first trace of 
wing-development. The appearance of these ridges is not, how- 
ever, always in stage 4. In a few instances I have noticed them 
in the previous stage, while in many cases they do not appear 
until the fifth stage, but either stage 4 or 5 seems to be the 
normal one for their appearance. ‘The development of the wings, 
like that of the lamellz, seems more closely connected with body- 
growth than with the moults. ‘This statement, however, requires 
some qualification, for, although it is not possible to describe any 
definite condition of wing-development as being connected with 
any particular moult, there seem to be one or two very definite 
stages correlated with the approach of the final ecdysis. This 
will, however, be referred to later. 
Stage 5. 
A further increase in the number of antennal segments takes 
place at the fourth moult, the third segment from the base again 
dividing into two equal parts. This 6-segmented condition of the 
antennz continues through the next four stages, in fact, until the 
commencement of the final nymphal stage is reached, when a 
change takes place. 
The condition of the labium remains the same as in the previous 
stage. 
Although no regular record has been kept of the rate of 
increase in the number of Malpighian tubercles, one nymph 
examined in the fifth stage had either 5 or 6 of these. The rate 
of increase in the number of these must become more rapid later 
Proc. Zoou, Soc.—1909, No. XVIII. 18 
