278 
Psyche 
[September 
consequently to extinction. 
And so this study of the venation of the two recent 
orders, the Agnatha and the Odonata, which to my mind 
represent the branches which separated early from the 
more primitive forms of the very similar Dictyoneuridse, 
and which have nothing in common with the Neuroptera 
and Plectoptera 16 , leads me to the conclusion that such 
characteristic features of the venation and the distribution 
of veins (in particular RS, partly M) of the Dictyoneuridse 
were preserved better in the dragon-flies and may-flies 
than in many Palseodictyoptera or Megasecoptera, in which 
the venation was too specialized or too reduced. May, 1923. 
P. S. My work was already in the press of the Russian 
Entomological Review when the July number of Psyche 
(30:1923, nos. 3-4) appeared, with an article by Aug. 
Lameere on “The Wing Veins of Insects/’ In this small 
but very valuable article, the author discusses chiefly the 
venation of the Palseodictyoptera, the dragon-flies and the 
may-flies, and in many respects comes to the very same con- 
clusion on the question of the interpretation of the venation 
as I have. 
In the treatment of RS in the dragon-flies and the may-flies 
we agree perfectly, aside from terminology. According to 
Lameere, also, the media of may-flies corresponds to the 
posterior branch (our MP), in Triblosoba, etc., and the 
media of the dragon-flies according to the author is MA 
(my terminology) . From a comparison of the Protodonata, 
I now entirely share this interpretation, according to which 
the dragon-flies lost MP. In the treatment of the cubitus 
we do not agree in everything, because the assertion of 
Lameere that the may-flies, as well as the dragon-flies, have 
lost CuA, is to my mind not entirely proven. I will not 
discuss here the venation of the other groups, and will note 
only that the conception of the author that there is a close 
relation between the Hemiptera and the Palseondictyoptera 
appears to me unlikely. According to my understanding 
of the venation of Eugeron, it is constructed entirely after 
the type of the Palseodictyoptera, and is far from the type 
16 The Plecoptera have to be included according to my understanding 
into the super-order Orthopteroidea. A similar view has been 
taken by Lameere (1917). 
