18 Journal New York Entomological Society. tVoi. xxiv, 



12. None of the apterygote forms, which have departed but little 

 from the ancestral condition (and the Lepismids may be taken as 

 forms " annectent " between the Apterygota and lower Pterygota), 

 show indications of a tendency to develop tracheal gills, while many 

 of them bear paranotal expansions of the pronotum and other tergal 

 projections (see Fig. i6, Plate II). 



13. Unlike the tracheal gills, the paranota have been retained in 

 the most diverse insects, being preserved in the prothorax of certain 

 Mantids (Fig. 9, Plate II), Heteroptera (Fig. 10, Plate II), Coleop- 

 tera (Fig. 13, Plate II), Lepismids (Fig. 16) etc., as well as in the 

 abdominal region in certain Phasmids (Figs. 11 and 14, Plate II), 

 etc., and the paranota also occur on many of the segments in numer- 

 ous "larval" forms (c. g., in immature Plecoptera and Ephemerids, 

 as shown in Figs. 15 and 18 of Plate II) and are specially well de- 

 veloped in certain Coleopterous larvae such as those of the Sylphidse, 

 of Psephcmis lecontei, and many others. This would indicate an 

 inherent tendency in the insect stem, toward the formation of lateral 

 integumental expansions, or paranota, and the fossil forms also ex- 

 hibit this tendency (see Figs. 8 and 12, of Plate II). 



14. Unlike the tracheal gills, the tendency toward the formation 

 of paranotal expansions is apparently inherent in the Arthropod stem 

 — at least in those Arthropods whose lines of development parallel 

 that of the Insecta — and finds opportunity for expression in the most 

 diverse forms. We thus find paranota developing in the Diplopods 

 (Fig. 17, Plate II), in the Crustacea (Fig. 19, Plate II), in the Tri- 

 lobites (Fig. 20, Plate II) and many other groups, and even in Arth- 

 ropods more remotely removed from the Insectan stem, this inherent 

 tendency may find opportunity for expression — although in certain 

 of these more remote forms, I am not certain that we are dealing 

 with structures strictly homologous with the paranota. Thus Berlese 

 (1906-1909) has figured a series of Acarina (Oribatidse) in which 

 can be traced the gradual development of lateral " pteriform " ex~ 

 pansions of the dorsal region, which are small in Oribatiila planth'aga 

 and caliptera, but become greatly developed in Oribatcs latipcs, while 

 in Oribates alatus these " pteriform " appendages actually become ar- 

 ticulated with the tergal region. Furthermore, they do not have to 

 pass through a tracheal gill stage in order to develop an articulation 

 with the tergite — as Woodworth would claim that integumentary ex- 



