96 
Psyche 
[March 
tera-like, and the Protorthoptera are in reality “Proto- 
blattoid” or Protoblattid-like, and it would be correct to 
state that the ancestors of the Mecoptera and other 
Holometabola were either Protorthopteroid or Protoblat- 
toid ; but since the Protoblattids are a little nearer the com- 
mon stem forms from which the others were derived, it 
is somewhat more accurate to describe the ancestors of the 
Holometabola, etc., as “Protoblattoid.” A study of the 
wings of such a primitive Mecopteron as Notiothauma very 
clearly indicates that the ancestors of the Mecoptera had 
(1) delicate tegmina, (2) wings which were broader in 
the distal half of the wing and were (3) broadly rounded 
apically. The wings were (4) incumbent in repose, and, to 
facilitate laying the wings back in repose, had developed 
(5) a break in the basal costal region, resulting in the 
formation of (6) a basicostal sclerite demarked from the 
rest of the costal vein, (7) a basal arch of the first anal 
vein with an accompanying (8) basal pocket or fold, and 
(9) a preclaval rima or crack which traverses the base 
of the cubital vein and aids in permitting the wing to be 
laid back in repose. (10) The costal area was very wide, 
and (11) cellules tended to develop in it. (12) The stem 
of Cu 1 was very short and (13) irregular cellules filled the 
cubital area. (14) The fore wings bore a jugalular lobe. 
Most of these features occur in the Protoblattids, and in 
many of their living representatives, the Blattids (indeed, 
some entomologists do not recognize the Protoblattids as 
an order distinct from the Blattids) ; but these features 
are not characteristic of the Megasecoptera and other 
forms which have been proposed as the types ancestral to 
the Mecoptera. I would therefore maintain that the ances- 
tors of the Mecoptera were Protoblattoid, and from such 
ancestors arose all of the lower Holometabola — and in fact 
of the Hemipteroid insects as well. 
The types intermediate between the Protoblattoids and 
the ancestral Mecoptera are as yet unknown, but the im- 
mediate ancestors of the Mecoptera must have been ex- 
tremely like those of the fossil Neuropteron Permorapisma, 
although the wings of Permorapisma itself, are not rounded 
2 Cui was probably forked in the ancestral Mecoptera. 
