ENTOGNATHY IN APTERYGOTES — TUXEN 



385 



teeth, the lobus internus of the first maxillae have no setae, and the 

 palpi are unsegmented. Unfortunately, the mouth parts are not drawn 

 in the head capsule. 



The prolarval mouth parts of Campodea are drawn in figure 2 in 

 ventral view after a slide made by Orelli. It is seen that they are very 

 much like those of the adult, the mandibles possessing all teeth and 



0.01 mm 

 Fig. 2. — Campodea rhopalota Denis. Prolarva. Head, ventral, antennae omitted. 



also the prostheca characteristic of Campodea, and the lobus internus 

 of the maxilla having all setae. The lobus externus could not be seen. 

 The important point is, however, that though the hypopharynx has 

 its final shape, the sternal sclerotization, the fulcrum, is only indicated. 

 It is also seen that the mandible proceeds farther backward than the 

 maxillae. 



The embryology of Anurida (Collembola) is best described by Fol- 

 som (1900), who, with regard to the mouth parts, says that a fold 

 appears on each side of the head in the region of the mandibles and 

 proceeds forward and backw-ard to the fundaments of the labrum and 

 the labium, involving the labial and clypeal folds "in such a way that 

 all three folds become one and enclose a single common cavity," His 



