SEXUAL CHARACTERISTICS OF THELIA 61 
megagnathic larvae while the preparation for this transformation 
is going on, female coloration and many other changes to be 
described are brought about. If, on the other hand, the Aphe- 
Fig. 14 Same as figure 13, seen in transmitted light. Chitin without melanic 
pigment (punctures in normal male), light; yellow pigment acting as absorber of 
actinic rays appears dark between punctures when present; melanin also appears 
dark. X 16.6. 
lopus has oviposited in a nymph during its fourth or fifth instar, 
the parasites will be small and have less effect upon the adult 
structures. 
