ONTOGENY 
RAGONFLY nymphs emerge from the egg 
in a form that is retained with but little 
alteration until they are grown and ready to 
transform. There are, of course, no wings, 
nor even wing buds present at hatching. 
The lateralabdominal appendages (cerci), 
also, are wanting. The labium, though 
\ already developed and ready for business, 
=x ‘is often quite different in the details of 
its armature, as shown in the accompany- 
ing figures. There are some characters 
such as the head tubercles of the new 
hatched green jacket nymph (fig. 17) (marks of past Macromian 
ancestral history?) that will be lost with the earliest moultings. The 
definitive nymph form is assumed after a few moults and while the 
nymph is still very small. 






Fig. 17. Nymph of the green jacket, Mesothemis simplicicollis. 1, new 
hatched, Ja, head enlarged, 1b, dorsal, 1c, ventral view of adbominal appen- 
dages; 2, second instar nymph of same. 
A detailed study of the form changes, moult by moult, in the nymph 
of Pantala flavescens through the first ten instars has been made by 
Miss Laura Lamb (’25, pp. 285-312). She has subsequently determined 
35 
