28 
Indian Forest Records. 
[Vol. Vltl. 
Early Instars. 
Sufficient material is not available to determine the normal number 
and the characters of each instar. Head measurements of larvae of 
various sizes are given on page 44 and the principal differences are 
summarised below. 
Setal Arrangement. —In the smallest larvae collected, length 
6*0 mm., there is essentially no difference in the setal arrangement. 
Mu is present on the abdominal segments and theta on the thoracic 
segments, (and therefore according to Fracker the instar represented 
is subsequent to the iirst moult); epsilon is also present as in the mature 
larva, but this seta as occasionally some of the pi and kappa groups, 
is extremely minute, and is scarcely visible at magnifications below 
100 . 
CROCHETS.—[Plate i, fig. 9]. In the smallest larvae (? second 
instar) the crotchets are few in number and distinctly uniordinal; in 
later stages shorter alternate crotchets appear at the sides of the planta 
but completely biordinal crotchets are not found until the last 
stages. 
SPIRACLES.—[Plate i, figs. 5, 6 and 7]. There is very consider¬ 
able change in the relative sizes of the spiracles. In the (?) second instar 
the spiracles on segment 8 [fig. 7] are very large, oval or deltoid, and 
more than twice as long as the prothoracic spiracle ; the abdominal 
[fig. 6] spiracles are minute, sub-circular, and about the diameter 
of the prothoracic spiracle [fig. 5].* In later stages the relative size of 
the abdominal spiracles increases, until they are sub-equal with the 
prothoracic spiracle, and are oval in outline. The size of the 8th 
abdominal spiracles decreases until they are about 1J- times the pro- 
thoracic spiracles. 
PROTHORACIC SHIELD.—[Plate i, fig. 4]. The design of the 
posterior area of the shield remains fairly constant; the earliest stage 
observed shows four teeth advanced between the beta setae, 2 large+1 
small in the lateral regions of the first row of teeth, and 8 to 10 teeth 
in the second row. Later instars show a progressive increase in the 
number of teeth in the lateral regions of the first and third rows and 
in the posterior zone. [The arrangement of teeth on the pronotal 
shield is probably not a specific character : Stebbing’s figure of the 
larva of Duomitus leuconotus shows a similar arrangement and larvae 
of Zeuzera spp. show a pattern of the same type]. 
* In mounted skins the abdominal spiracles are circular and those on segment 8 
deltoid, but in spirit specimens all spiracles appear oval in outline as illustrated. 
[ 256 ] 
