PHILIP A. MUNZ 33 



5. Migration outivard of the base of Mi^. — This tendency is cor- 

 related somewhat with the preceding, but seems to be independent 

 of it to a certain degree. Most genera among the Agrionidae, 

 Pseudostigmatinae, Lestinae, and Megapodagrioninae have Mia 

 arising about three or four cells beyond the fork of M1+2, or at least 

 rather near it. Perilestes, (fig. 70) however, which has M1+2 fork- 

 ing about two-thirds of the way out has Mia arising below the outer 

 end of the stigma, or about one-fourth of the wing-length beyond 

 M2. This is true to a lesser degree in some of the Coenagrioninae 

 such as Platycnemis (fig. 74), Antiagrion (fig. 81), Ilyponeura (fig. 

 82), Agriocnemis (fig. 104), Ceriagrion (fig. 117) and others. It is 

 not on the whole an important character, but does occasionally 

 seem worthy of notice. 



6. The position of the second antenodals before the arciilus. — In 

 those Agrionidae with many antenodals, there is a tendency for two 

 of the costal antenodals to become more strongly developed than 

 the others, and to be in line with two corresponding ones of the sub- 

 costal series, while at the same time the second of these pairs is 

 directly above the arculus. In Epiophlebia (fig. i) this second pair 

 lies considerably beyond the level of the arculus; in Polythore (fig. 

 2) and Euthore (fig. 3) it is at that level, in Cora (fig. 5) and Chal- 

 copteryx (fig. 4) before it. In the Agrioninae, i.e. the legion Calop- 

 teryx, there is no evident hypertrophy of antenodals, but in the 

 Epallaginae the tendency is again e\-ident and the number of 

 antenodals is reduced, until the two pair typical of the Cocnagri- 

 onidae remain. Here, as in the Polythorinac and some Epallaginae, 

 in some of the most highly developed forms: Lestoidea (fig. 45), 

 Perilestes (fig. 70), Chorismagrion (fig. 69). Ceratura (fig. 102), 

 Agriocnemis (fig. 104), Ilemiphlebia (fig. 106), Caconeura (fig. 143), 

 Protoneura (fig. 146), Selysioneiira (fig. 153) and others, the second 

 antenodals are distinctly before the level of the arculus. Since 

 this tendency rarely is manifest except in the highest memi)ers of 

 the respective groups, it seems indicative of specialization. 



7. The tendency for the quadrangle to become acute distally. — Dr. 

 Needham (1903a) has taken as the primitive type of quadrangle 

 one square distally and Mr. Williamson (1913) agrees that "in the 

 relations of MA," the Calopteryginae (Agrionidae of this paper) 



MEM. AM. ENT. SOC, },. 



