1930 ] 
The Mecopteron Notiothauma reedi 
95 
wing, are frequently broken by “pellucidse” (maculae 
pellucidae) or “bullae,” which are clear spots. Their true 
function is not definitely known. Only a few of these are 
indicated in the figures. 
The cellules of the hind wing are not as irregular as 
those of the fore wing, and the venation of the hind wing 
is more “normal” than that of the fore wing, particularly 
in the medial field. M 5 is not labelled in Fig. 2, but it can 
be identified by the dotted line running up from M 3+4 , which 
crosses M 5 . Since M 4 is not fused with Ciu in the hind wing, 
I am inclined to think that it is not fused with Cui in the 
fore wing either, so that tjie vein labelled M 3 in the fore 
wing is probably M 3+4 . 
The stem of Cu is extremely short in the hind wing 
(Fig. 2) and its fork looks more like a cross vein than a 
fork. Cu 4 is not united with M, and it forks into Cu 4 a and 
Cu 4 b, which is a very primitive feature not retained in 
other living Mecoptera, and the character of Cu, with its 
short stem, is suggestive of a Protoblattoid origin. 
The first ana] vein of the hind wing is not markedly 
curved at its base, and the second anal vein parallels it 
rather closely. The trunk of the third anal gives off three 
branches anteriorly (unilaterally) which leads me to think 
that the third anal of the fore wing branches in the same 
fashion. The fact that the anals exhibit no tendency to loop 
up as they do in the fore wings of certain Trichoptera, etc., 
shows that Notiothauma is a rather primitive Holometa- 
bolan, and its venation and wing characters indicate that 
it is one of the most primitive members of the order 
Mecoptera. 
In referring to the “Protoblattoid” or “Protorthopteroid” 
ancestors of higher insects, it should be borne in mind that 
the Protoblattids and Protorthoptera are fundamentally 
alike, and the division into these two groups is one of con- 
venience rather than a division into groups of ordinal rank, 
since the Protoblattids and Protorthoptera intergrade so 
markedly that it is doubtful that they represent groups of 
more than subordinal rank. Since the two groups thus in- 
tergrade, the terms “Protoblattoid” and “Protorthop- 
teroid” are practically interchangeable because the Proto- 
blattids are in reality “Protorthopteroid” or Protorthop- 
