108 ENTOMOLOGICAL NEWS [April, '22 



These combine as shown in the following lists : 



By this scheme cornanc/ie appears to he a pale a.rHlcna. 

 The other species are various intermediate combinations of 

 these paired characters. Comanchc 20 is also the only desert 

 species of this group. Probably it has entered the desert from 

 the east. This axillcna group represents the very apex of 

 North American Odonate evolution, if we consider the Libel- 

 lulidae as the apical Odonate family. 



Group 9. Depressa Linn. PI. IV, fig. 25. England to Russia and 

 Persia, south to Sicily. Ponds. 21 



This is definitely a European offshoot from the Plathemis 

 stock. It may have been traded to Eurasia when 4-nmcnlata 

 came to America, but the difference between it and the two 

 species of Plathemis is great enough to suggest that it branched 

 off much earlier. 



Group 10. Quadrimaculata Linn. PI. IV, fig. 20. England to 

 Spain, Kashmir and Japan. In America from Newfoundland to 

 Alaska, south in the mountains to North Carolina and California. 

 I cannot trace Muttkowski's 22 Arkansas record. 



The nearest relative of this species is angelina of Japan. 

 Qnadrimaculata probably entered North America recently as 

 it has no near relatives on this continent. It may have come 

 in when the very modern EnaHagina cyathigerum entered Eur- 

 asia, as the two have the same distribution. It is very modern 

 and highly specialized in its intense activity. 



Group 11. Fulva Muell. PI. IV, fig. 27. England to Italy, Den- 

 mark to Transcaucasia. Moor swamps and slow-flowing brooks, 

 more (often found) in the mountainous regions. 23 



20 Is it possible that our Odonata tend to form a pale desert fauna ? 

 Offhand the writer recalls Ophiogomphus ncvadcusis, Gomphus ncva- 

 dcnsis, Complins intricattis, Sympetrum madidum, Syinpctruiii corntp- 

 tum, LibcIIula composite and Ischnura barbcri. 



21 Frohlich in Die Odonaten u. Orthopteren Deutschlands, p. 13, 1903, 

 states that this species is found from May to July, common about all 

 smaller pools, swamp and peat ponds. 



22 Catalogue of the Odonata of North America, p. 140, 1910. 



- ? Frohlich, Odonaten u. Orthopteren Deutschlands, p. 11, Jena, 1903. 



