458 THE INVERTEBRATA 



legs occur. Finally these abdominal embryonic legs disappear and 

 the insect may then hatch with thoracic legs only (Fig. 319 E). These 



Fig. 319. To illustrate the principles of Berlese's theory. A, B and C are 

 3-> 3*- and 4-day embryos oi Hylatoma berberidis in the Protopod oligomero, 

 Protopod polymero and Polypod stages of development. D is the Oligopod 

 stage of Melolontha. Corresponding with these are the early larval forms, 

 E, oi Platygaster (protopod), F and G of Figites anthomyiarum (protopod poly- 

 mero and polypod respectively) and H, of Sitaris (campodeiform or oligopod). 

 A, B, C and D, after Graber; E, after Kulagin; F and G, modified after 

 James; H, after Korschelt and Heider. A, antenna; A i, first abdominal leg; 

 Md. mandible; Mz, second maxilla; Mi +2, first and second maxillae ; T3, 

 metathoracic leg. 



Stages are known as the Protopod oligomero (imperfectly segmented 

 abdomen), Protopod polymero (segmented abdomen), Polypod (with 



