69 
in the direction of nakedness, which is exemplified in the ontogeny of 
most Sphingid larvae. Again, the very fact of the horn alone being 
left with its coat of bristles intact, suggests that they were an older 
character in that situation than elsewhere as a reason for their persist¬ 
ence ; an explanation which would, so far as I understand it, sweep 
away the principal argument in favour of their having originally 
occupied the whole skin surface. It would seem just as probable that 
they should be first developed on the horn, as that the thoracic seg¬ 
ments of some Lachneids should be ahead of the abdominal ones in 
the development of their hairy covering. 
A Classification of British Sphingids on Larval Characters. 
First stage pale, with greenish tinge ; a larger or shorter caudal 
born on 8th abdominal segment, bearing tubercles i on summit; 
primary tubercles single-haired, except iii of meso- and meta-thoracic 
segments, which bear two seta?; bases of secondary hairs frequently 
developed into mammillre, and sometimes pigmented (one or both of 
these characters usually well developed in middle 3rd or 4th instars), 
v normally situated as pre-spiraeular towards anterior margin of 
segment, iv wanting on meso- and meta-thoracic segments. Abdo¬ 
minal segments with eight sub-divisions. 
(A) Dorsal tubercles i and ii on meso- and meta-thoracic segments 
set as anterior and posterior on separate sub-segments ; an 
enlarged 1st sub-segment, consisting of three of the normal 
sub-divisions ; hairs simple-ended or knobbed, not bifid. 
(I.) With 1st and 2nd abdominal segments swelled and the 
thoracics retractile within them ; well developed eye spots 
on 1st and 2nd abdominal segments (adult characters). 
(a) i. Fairly developed caudal horn, Hip-potion eelerio. 
ii. Small caudal horn, Kamorpha elpenor. 
iii. Caudal horn absent in all stages, Theretra porcellus. 
(II.) Without swelled 1st and 2nd abdominal segments, and 
producing rudimentary ocellated spots on many or all 
segments. 
(a) i. With single row of ocellated spots, Phryxus livornica. 
ii. With double row of ocellated spots, Celerio gallii, 
euphorbia e 
(B) Dorsal tubercles on meso- and meta-thoracic segments with 
bases conjoined or touching, situated on the same sub- 
segment ; no enlarged first sub-segment; hairs in some 
groups more or less forked (bifid). 
(I.) With forked hairs, but without tumid thoracic segments. 
(a) Primitive setse only in 1st instar, except on horn. 
i. With bifid character of hairs less strongly developed in 
1st stadium, Sesia stellatarum. 
ii. With bifid character of hairs much accentuated in 1st 
stadium. 
a . Hairs pale green, Hemaris fuciformis. 
p. Hairs black, Hemaris tityus. 
(b) With dense coat of slightly bifid secondary hairs in 1st 
stadium, and more or less triangular heads in later stadia. 
* This species has iv and v on 1st abdominal segment situated on a small oval 
plate beneath spiracle. This may prove to be a special feature of the species and 
its variants, or more probably it is a charatcer of the group ii. 
