PROC. ENT. SOC. WASH., VOL. 24, NO. 2, MAR., 1922 75 



It is very surprising that Folsom, 1900, Imms, 1906, and 

 others, who have made a detailed study of the mouthparts of 

 the apterygotan Anurida, have wholly missed the significance 

 of the parts of the maxilla in this insect, thus showing very 

 clearly that is impossible to interpret the parts in insects aright, 

 without first making a study of related forms, and comparing 

 the parts with those of the Crustacea. Thus, Folsom and Imms 

 apply the term "galea" to the incisor process of the lacinia 

 labeled "a" in Figs. 20 and 21 of Anurida, and they restrict the 

 term "lacinia" to the right hand lacinular plate labeled "le" 

 in Fig. 20, while Imms applies the designation "maxillary palp" 

 to the left hand lacinular process labeled "le" in Fig. 20. 

 Folsom, 1899, has also misinterpreted the parts of the lacinia of 

 the maxilla of Orchese/la, as may be seen by comparing his figure 

 of the parts with Fig. 31 of the present paper. 



The lacinial fringe ofNicoletia (Fig. 19) is quite different from 

 that of Machilis (Fig. 27) and this feature adds further confirma- 

 tion of the contention that Machilis should be placed in an order 

 distinct from that containing Nicoletia and the other Lepisma- 

 tidae. On the other hand, the lacinia of Nicoletia (Fig. 19) is 

 quite like that of certain pterygotan insects such as the one 

 shown in Fig. 18, since the laciniadentes, or incisor processes 

 "a" of Fig. 19, evidently correspond to the incisor processes 

 labeled "a" in Fig. 18, and the process labeled " b " (provisional- 

 ly homologized with the midappendix " b " of other apterygota) 

 in Fig. 19 is apparently the homologue of the appendage 

 labeled "b" in Fig. 18. ' The small processes labeled "le" m 

 Fig. 19 doubtless correspond to the processes labeled "le" in 

 Fig. 27, but they appear to be wanting in Fig. 18, unless they 

 are represented by the seta-like structures borne on the lacinia, 

 but not represented in Fig. 18. 



Several investigators have recently questioned the advisa- 

 bility of grouping the Protura with the rest of apterygotan 

 insects, since they claim that the Protura are not true insects, 

 but belong in a class by themselves or the Protura are even 

 regarded by some investigators as being nearer the "myriopods" 

 than insects. The head, thoracic, and terminal abdominal 

 structures of the Protura, however, are clearly insectan, as is 

 further borne out by the structure of the maxilla, as one may 

 readily see by comparing the maxilla of the insect shown in Fig. 

 16 with that of the proturan shown in Fig. 17, and I can see no 

 reason why the Protura should not be grouped with such aptery- 

 gotan insects as Tomocerns, Tetrodontophora, and similar forms 

 with which they have so much in common. The Protura are 

 evidently an early offshoot of the primitive Apterygota, from 

 which the sminthurids and entomobryids were also derived, and 

 the evidence derived from the studv of the maxillae of the Pro- 



