386 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 1 37 



beautiful figures 5 and following show the development of this plica 

 oralis, but besides views of the head from in front he gives also side 

 views and purely ventral views, and from these it is seen that as long 

 as the second maxillae are free the mandibles and first maxillae 

 occupy a normal position to the rest of the head (stage 5, figs. 20, 21 ), 

 but when the labium is coalesced with the oral folds the other mouth 

 parts become long and as if retracted backward into the head (stage 7, 

 figs. 24, 25, 29, 30). A rotation of the first maxillae as described by 

 Uzel in Camp odea is seen by comparing figures 11 (stage 3) and 12 

 (stage 4) with figures 21 (stage 5) and 29 (stage 7). A correspond- 

 ing rotation of the second maxillae cannot be seen, as lobi externi as 

 well as the palpi are lacking. Folsom states expressly as his opinion 

 (p. 139) that "the entire gular region is labial in origin." He also 

 notes that the lingua and superlinguae (glossa and paraglossae) de- 

 velop independently of the fulcrum (his basal stalks), which latter 

 form "in a groove which is but a longitudinal evagination of the 

 maxillary pocket" (p. iii). In stage 7 (fig. 29) this stalk is said to 

 be fully developed. 



The postembryonal development of CoUembola has been investi- 

 gated by several workers, most recently by Lindenmann (1950), but 

 a description of the mouth parts and the head of the very first stages 

 is nowhere given and I have not seen any specimens myself. 



The embryology of Protura is unknown. As to the postembryonal 

 development, it has been known since Berlese that they have anamor- 

 phosis, and the present author (Tuxen, 1949) has definitely deter- 

 mined the kind of anamorphosis. I distinguished a prelarval stage 

 with 9 abdominal segments and very different from the following 

 stages, and after this stages with 9, 10, 12, and 12 segments before the 

 adult stage. There is no doubt in my mind that my prelarva cor- 

 responds to the prolarva in the development of Campodea and Japyx 

 (see above), and I willingly change the name from prelarva into pro- 

 larva. But I am strongly opposed to the names proposed by Paclt 

 (1956b, p. 59), who substitutes the word nymph for the word larva 

 and further introduces the words protonymphs, deutonymphs, and 

 tritonymphs, which have a definite meaning in arachnids not at all 

 comparable with the present case. Also the change of larva into 

 nymph seems to me superfluous, the rigid distinction between the 

 names of juvenile stages with or without metamorphosis being un- 

 happy as it suggests a distinction more fundamental than it really is 

 (see also Imms, 1957, p. 224), and furthermore the word larva is 

 always used in reference to apterygotes. 



The prolarva of Protura is different from later stages in many 



