30 University of Michigan 



15. Heteragrion erythrogastrum Selys 



Figures i, 30, 31, 58, 64, 71, 84, 85, 125, 126, 146, 147 



Calvert (3) and Ris (8) have pointed out that the processes 

 of the male inferior appendages are small and variable. In 

 some specimens they are invisible in a profile view but may be 

 detected in an oblique posterior view. De Selys' reference of 

 the species to his group 2, rather than 3 where it really belongs, 

 was due doubtless to his material having the processes con- 

 cealed or minute. By venational characters, however, he 

 should have referred it to group 3 as the arculus is distal to 

 the cubito-anal cross-vein from .3 to .5 mm., while the anal 

 vein separates from the posterior border usually near the 

 cubito-anal cross-vein, distad .1 to .2 mm. 



Calvert (3) and Ris (8) have briefly described the teneral 

 male. Such specimens, in their abdominal pattern, suggest the 

 adults of allied species {chrysops, etc.). The thoracic pattern 

 of such teneral males is similar to that of the adult female. As 

 the male matures the pale stripes, adjoining the middorsal 

 black, blacken and disappear at least in some cases before the 

 pale humerals are lost. 



Colombian specimens are larger with a tendency to fewer 

 postnodals than specimens from Central America, as shown by 

 the following data : 



Abdomen male, Colombia 35 to 42, average 37, Canal Zone 

 34 to 35. 



Abdomen female, Colombia 30 to 33, average 31; Canal 

 Zone 28. 



Hind wing male, Colombia 24 to 26; Canal Zone 22 to 23. 



Hind wing female, Colombia 25 to 26; Canal Zone 22.5. 



Postnodals front wing male, Colombia 16 to 18; Canal Zone 

 16 to 18. 



