Fig. 3. I.ongitudinal seclions of the walls of Ihe sacs of the pond larva, A -D of 
a young larva (5 mm.), E-(l of a full grown larva. A is a section of the ventral 
wall, Ihc dimensions are the following : Total thickness 1(5,3 //, chiline wall 6,7 //, 
length of the 4ieads» 1,8 u, breath of the dark siripes 1,4 //, of the grev stripes 
(1.5 n. B section of the wall of the dorsal side; dimensions': Total 7,0 //, Pigment 
layér 1,8 u, chitine 4,2 t(. «heads» 0,8 //, dark stripes 1,5, grey stripes 6,5. C part 
(T the ventral side and the one end. D part of the lateral surface, the ends of 
two of the dark stripes are seen to he intercalated between the others. Dark stri- 
pes 1,8 //, grey stripes 0,5 //. E ventral side; dimensions: Total 21,8 //, chitine 
10.2 //, «heads» 3,5 //, dark stripes 3,2 //, grey stripes 0,6 //. F florsal side; dimen¬ 
sions: Total (without pigment cells) 9,2 //, chitine 6,7 //, «heads» 3,5 //, dark stripes 
3.2 //, grey stripes 0,6 //. (5 parts of the wall towards the end, where the stripes 
hecbme very narrow. All figures drawn with camera lucida, (with Leilz obj. 6, 
Winkel complan. oc. 5 (enlarged ca. 800 diam.), the other figures with E. 8, W. compl. 
5 (ca. 1200 diam ) 
