ENTOMOLOGY 



kind of head, with long moniliform antennae, and agree in the general 

 structure of the mouth parts; the number of body segments is nearly 

 the same, the legs and claws are essentially alike, and cerci and paired 

 abdominal stylets are present in the two genera, not to mention the 



FIG. 6. Section of Scolopendrella immaculata. b, brain; c, coxal gland; /, fore intes" 

 tine; h, hind intestine; m, mid-intestine; n, nerve chain; o, opening of silk gland; od, oviduct; 

 ov, ovary; 5, silk gland; u, urinary tube. After PACKARD. 



correspondences of internal organization. Indeed, it is highly prob- 

 bable, as Packard maintained, that the most primitive insects, Thysa- 

 nura (and consequently all other insects) , originated from a form much 

 like Scolopendrella. A singular thysanuran, Anajapyx vesiculosus 

 (Fig. 7) was discovered by Silvestri, who regarded 

 it as being in many respects the most primitive in- 

 sect known, combining as it does characters of 

 Symphyla, Diplopoda and Campodea. 



Silvestri discovered also a peculiar arthropod, 

 Acerentomon doderoi (Fig. 8) for which he made a 

 new order Protura. Berlese added two genera to 

 this order, namely, Eosentomon and Acerentulus; and 

 according to good authority Protapteron indicum 

 Schepotieff belongs to the former genus. Silvestri, 

 followed by Borner, put Protura among Aptery- 

 gota; but Berlese, who grouped these forms under 

 the name of Myrientomata, found that they had 

 myriopodan as well as insectean affinities; and 

 Rimsky-Korsakow argued that Myrientomata 

 FIG. 7. Anajapyx cannot be rightly regarded as insects, but logically 



vesiculosus. Length, 2 ^ J , 



mm. After SILVESTRI. constitute a class by themselves; and that this class 

 does not form a direct link between myriopods and 

 insects, but that all these groups came from the same ancestral 

 stock. Protura have actually little in common with insects; the pecu- 

 liar structure of the mouth parts and genitalia excluding them from 

 the group Apterygota. 



