564 Notes in 1887 upon lepidopterous larve, éc. 
been already alluded to. The terrifying mark becomes 
slightly more distinct ; the red anal spine is relatively 
shorter and less conspicuous. Distinct differences in 
the shade of green which forms the ground colour are 
now seen in some of the larve, but they are more 
common in the next stage. 
The larve varied in length from 22°25 to 27 mm. 
in the resting-stage before the 8rd ecdysis. The 3rd 
stage lasted for about seven days. 
Stage IV.—The larve were, on the average, about 24 
to 25 mm. in length at the beginning of the stage, 
although they varied above and below these limits. The 
appearance of the larva is shown in Plate XVIL., fig. 5 (nat. 
size), and the differences between this and all previous 
stages are seen to be very striking, for the conspicuous 
spines are lost, together with the red anal spine and the 
small tubercles. The shagreen dots, oblique stripes, and 
sub-spiracular line remain, the latter being especially 
conspicuous and edged above with a dark border. 
Smerinthus is similar in retaining the shagreen dots in 
the last stage, while Sphinx loses them. ‘The shade of 
green ground colour is different above and below the sub- 
spiracular, being much darker below, and the surface of 
the three thoracic segments above the subspiracular, is 
of a deeper green than the corresponding part of the 
abdominal segments. Both these distinctions are also 
characteristic of certain Sphingide (Sphinx ligustri, and 
the green form of Acherontia atropos: Trans. Ent. 
Soc. Lond., 1886, p. 144). The ground colour also 
varies considerably in the different individuals, and 
the tints are almost exactly similar to those which 
have been the subject of experiment in Smerinthus 
ocellatus, and which also occur in S. populi. The differ- 
ences may be best classified as bright yellowish green, 
dark bluish green, and intermediate. The yellowest 
larve possess a distinct bright green colour below the sub- 
spiracular line, while those which are of a duller green 
above, are characterised by a deep bluish green colour 
below. This almost exactly corresponds with the differ- 
ences in Smerinthus ocellatus, where the shade of the 
under surface is always the most extreme test of the 
individual variations. 
The strongly-marked separation between the abdo- 
minal segments remains, while the thoracic segments 
