1930 ] 
The Mecopteron Notiothauma reedi 
91 
in the vein labelled M 3 in Fig*. 1 — although it may possibly 
continue on down and fuse with Cui instead, but the latter 
view is not very probable (although it should be considered 
as a possibility), because it would leave the vein labelled 
M 3 unaccounted for. I am therefore inclined purely pro- 
visionally to interpret the fork of M just distad of the 
dotted line running up from the label M in Fig. 1 as the 
forking of M into M i+2 and M 3+4 as is indicated by the 
labelling. The fork at the hyaline spot labelled b in Figs. 
1, 3, 4, 5 and 6, would then be the forking of Mi + 2 into M 4 
and Mo. Where the forking of M 3+4 into M 3 and M 4 is, I do 
not know, although I am inclined to think that it may be 
just basad of the dotted line running up from the label M 3 
in Fig. 1. If this be correct, M 3 would be the vein so labelled 
in the Figure, while M 4 would be the short vein extending 
to and fusing with Cu 4 in Fig. 1. On the other hand, this 
short vein may be merely a cross vein between vein M 3+4 
and Cui, in which case the vein labelled M 3 in Fig. 1 would 
in reality be vein M 3+4 . I have provisionally followed the 
former view and have labelled the median veins as though 
M 4 had fused with Cu 4 in Fig. 1. There is such a discon- 
certing tangle of cellules (which are more elongate and 
quadrangular in the medial region than in the cubital 
region) in the medial region, however, that I would not 
insist on the interpretation of the courses of the branches 
of M indicated by the labelling, and the final interpretation 
of these veins must await the study of the pupal trachea- 
tion, or the comparison with some less complicated vena- 
tion in the fore wing of some as yet unknown Mecopteron. 
Merope and “ Protomerope ” however (both of which are 
related to Notiothauma) are primitive Mecoptera with a 
less complicated venation which shows no indication of a 
fusion of M 4 with Cu 4 , and this fact makes me suspect that 
the vein labelled M 3 in Fig. 1 is in reality vein M 3+4 and the 
forking of this vein into M 3 and M 4 occurs further out 
toward the distal half of the wing, and the labels should 
therefore be shifted accordingly in Fig. 1. The develop- 
ment of the medial field is much greater in Notiothauma 
than in most Frotoblattids, but some of the Protoblattids, 
such as Eucaenus, have a four branched media such as 
the ancestors of the Mecoptera must have had. 
