6 EN TOMOLOGY 
Scolopendrella, now placed either among Diplopoda or else 
in a class by itself, Symphyla, presents a remarkable combina- 
Section of Scolopendrella immaculata. b, brain; c, coxal gland; f, fore intestine; 
h, hind intestine; m, mid intestine; m, nerve chain; 0, opening of silk gland; od, 
oviduct; ov, ovary; s, silk gland; uw, urinary tube.—After PAacKarp. 
tion of diplopodan and insectean characters. Scolopendrella 
(Fig. 6) and the thysanuran Campodca have the same kind 
of head, with its long moniliform antennz, and agree in the 
general structure of the mouth parts; 
the number of body segments is nearly 
the same, the legs and claws are essen- 
tially alike, and cerci and paired abdom- 
inal stylets are present in the two genera, 
not to mention the correspondences of 
internal organization. Indeed, it is 
highly probable, as Packard maintained, 
that the most primitive insects, Thys- 
anura (and consequently all other in- 
sects), originated from a form much like 
Scolopendrella. A singular thysanuran, 
Anajapyx eee (Pig 7), mas 
lately been discovered by Silvestri, who 
regards it as being in many respects the 
Anajapyx vesiculosus. Most primitive insect known, combining 
Length, 2 mm-—After 4s it does characters of Symphyla, Diplo- 
SILVESTRI. : ‘4 bs 
poda and Campodea. 
The following diagram (lig. 8) expresses very crudely one 
view as to the annelid origin of the chief classes of Arthro- 
poda. 
