1930] The Mecopteron Notiothauma reedi 85 
Protoblattoid ancestry for the Mecoptera, instead of indica- 
ting an ancestry for the Mecoptera in forms like the Me- 
gasecoptera or even the Palseodictyoptera. 
The Megasecoptera and Palseodictyoptera are Archip- 
terygota, or insects incapable of folding the wings along the 
abdomen in repose, while the Protoblattids and Protor- 
thoptera are Neopterygota, or insects capable of laying the 
wings along the abdomen in repose, and the Protoblattids 
and Blattids typically hold the wings in the recumbent posi- 
tion in repose (i. e., the wings laid flat, one on top of the 
other, on the top of the abdomen) and it is a very signifi- 
cant fact that Notiothauma holds its wings in the incumbent 
position in repose, so that this archaic Mecopteron must 
have been descended from Neopterygotan ancestors rather 
than from Archipterygotan ancestors such as the Megase- 
coptera, etc., regarded by Handlirsch and Tillyard as the 
ancestors of the Mecoptera. (See Plate 3) 
The basal arch (ba of Figs. 1 and 7) of the first anal 
vein, forming a typical “basoplica,” together with the fold- 
like depression, like that described by Crampton, 1927 
(Psyche, 34, p. 59) and 1928 (Bull. Brooklyn Ent. Soc., 23, 
p. 113) in the Blattids, Isoptera, Orthoptera, Cicadas, Tri- 
choptera, etc., which have developed these structures in 
connection with laying the wings along the abdomen in re- 
pose, likewise indicates a Neopterygotan ancestry for the 
Mecoptera. 
The formation of cellules in the wings of the Protoblat- 
tids Asyncritus, Adiphlebia, etc., suggests the beginnings 
of a tendency to form cellules in the fore wings — a ten- 
dency which has been carried to an extreme in Notiotha- 
uma. It should be noted that it is not necessary for all of 
the Protoblattids or for all of the Mecoptera to exhibit this 
tendency in order to derive the Mecoptera from a Proto- 
blattoid ancestory, since, according to the adumbration 
theory, some members of an ancestral group may exhibit 
tendencies which later reappear in some members of a de- 
rived group without these features being exhibited by all, 
or most, of the members of either group, as has been dis- 
cussed elsewhere. It is therefore illogical to demand that 
all of the Protoblattoids shall exhibit a tendency toward the 
formation of numerous cellules, in order to derive such a 
