PHILIP A. MUXZ 



27 



generalized condition. They fall under two or three general heads 

 and may be so treated in their discussion. First come those which 

 may be classified under "X'^ein Reduction," secondly, those having 

 to do with "Vein Shifting," and as a last group "Miscellaneous 

 Features." 



Vein Reduction 

 I. Reduction in the number of supplementary sectors. — This is one 

 of the most evident means of specialization within any group which 

 possesses such sectors, as well as in the whole suborder, of which 

 the two highest subfamilies have none. A comparison of the dif- 

 ferent subfamilies in this regard may be made in a general wa\' by 

 choosing for each one as its most typical genus the one after which 

 it is named. In Table I this has been done, the figures indicating 

 the number of sectors between the veins listed at the top of the 

 columns. The figures are for the front wings. 



Table I 

 The Number of Supplementary Sectors present in the Sub- 

 families of Zygoptera 



Subfamily Genus and 



Species 



Polythorinae Polythore 



gigantea 

 Agrioninae Agrion 



Virgo 

 Epallaginae Epallage 



fatima 

 Disparocyphinae Disparocypha 



biedermanni 

 Megapodagrioninae Megapodagrion 

 ■ erin V5 



Ml- Mia- M2- Rs- M3- M,- Cui- Cu2 Total 

 M,a M2 Rs Mj M4 Cui Cu2 Margin 



040 



O 



7 8 8 3 S 45 



3 4 4 4 4 28 



.20000 8 



o I o o o s 



Lestinae 



Lestoidinae 



Pseudostigmatinae 



Coenagrioninae 



Protoncurinae 



Lestes 



reclangularis 0222 

 Lestoidea 



000 



conjiincta 

 Pseudostigma 



aherrans 

 Coeti agrion 



piiella 

 Protoneiira 



capillaris 



20000000 



III I I o I 



00000000 



00000000 



MEM. AM. ENT. SOC, 3, 



