10 
Indian Forest Records . 
[Vol. VII. 
Segment 8 with IV, V slightly ventro-cephalad of the spiracle ; 
VII variable, nmsetose, long or bisetose, long and short. Segment 9, 
the shield of II on both sides confluent dorsally ; I, III on one shield ; 
IV, V, VI on one shield ; VII unisetose. Anal shield with 4 setae. 
The larval characters of the genus Hyjpsi'pyla therefore appear to 
be :—circle of crotchets complete, triordinal prothorax with lib twice 
as far caudad of Ha as Ha is of la ; abdominal segment 3 with IV 
dorso-cephalad of V ; pinacula strongly chitinised ; ocellar arrange¬ 
ment subrectangular. 
The following Table 1 gives the measurements (made by Mr. N. C. 
Chatterjee) of the width of the head in the case of 57 larvae :— 
Table 1 —Measurements of the Width of Head of H. robusta larvae . 
First Instar. 
SECOND INSTAR. 
Third Instar. 
Fourth 
INSTAR. 
mm. 
mm. 
mm. 
mm. 
mm. 
mm. 
•35 
•75 
1-0 
1-5 
2-0 
2-25 
•4 • 
•75 
1-0 
1-5 
2-0 
2-35 
*5 
*75 
1-0 
1’5 
2-0 
2*35 
'5 
*75 
1-25 
1*5 
2-0 
2-5 
•5 
*75 
1-35 
1*5 
2*0 
2-5 
•8 
1*35 
1‘65 
2-0 
2‘5 
•85 
1*35 
1-65 
2‘15 
2*5 
•9 
1-4 
1-65 
2*15 
2*5 
1*0 
1-45 
2*15 
2*5 
1-0 
2*15 
2-5 
1-25 
2*2 
2-5 
1-25 
Changes in the larval colour. 
A reference to Table 8 p. 28 will show the colour changes observed 
to take place in the case of individuals. There is not much variation 
in colour during the first three stages, which display several shades of 
brown, but in the fourth stage there is a very perceptible sequence of 
colour changes. Immediately after the moult a fourth stage larva 
is of a dark or reddish-brown colour. This gradually fades to a pinkish- 
brown, changing subsequently to purple or reddish-blue, and finally 
to a light blue which frequently has a greenish tinge. The light blue 
colour is characteristic of the mature larva just before pupation and 
of the mature hibernating larva. The factors influencing the colour 
changes are unknown, but it may be noted that the fluid escaping from 
the body of a punctured pupa is invariably bluish-green. 
[ 155 ] 
