126 



Smith and Pritchard: Odonata 



— Inferior anal appendages noticeably longer than the 

 superior Sympetrum (in part) 



24. Mental setae to 4 Ladona 



— Mental setae 8 to 15 (fig. 4:1U) 25 



25. Margin of median lobe of labium crenulate on its distal 

 margin; abdominal segments 7 to 9 with dark, shining 

 middorsal ridges Plathemis 



— Margin of median lobe of labium evenly contoured; 

 abdominal segments 7 to 9 without such ridges 26 



26. Abdomen with lateral spines present on segments 8 

 and 9; dorsal hooks normally present on abdominal 

 segments 3 to 8, those on 7 and 8 rudimentary and 

 hidden among scurfy hairs Libellula (in part) 



— Abdomen with lateral spines vestigial on segments 8 

 and 9; dorsal hooks absent Belonia 



27. Apical third of inferior and lateral anal appendages 

 strongly decurved (fig. 4:13(7) 28 



— Apical third of all anal appendages straight, not 

 decurved (fig. 4: 13t) 29 



28. Minute lateral spine on abdominal segment 9; lateral 

 setae of labium 11 or 12 Lepthemis 



— No lateral spines on abdomen; lateral setae of labium 

 7 to 9 Erythemis 



29. Postocular distance equal to or greater than the length 

 of the eye when viewed from above; eyes usually small 

 and not very prominent (fig. 4: 10a, b, d) 30 



— Postocular distance less than the length of the eye 

 when viewed from above; eyes large and prominent on 

 a somewhat triangularly shaped head (fig. i:10g-i) . 36 



30. Lateral anal appendages nearly as long as the superior 



31 



— Lateral anal appendages one-third to two-thirds as long 

 as the superior; crenulations of lateral lobes shallow 

 or absent (fig. 4:11;') 33 



31. Crenulations of the distal margin of the lateral lobe 

 obsolete, merely indicated by about 15 single spinules; 

 abdomen abruptly rounded to tip; caudal appendages 

 protruding but little beyond the ventral margin of 

 segment 9 Pseudoleon 



— Crenulations of the distal margin of the lateral lobe 

 shallow to deep, with groups of 2-7 spinules on each 

 tooth 32 



32. Crenulations on lateral lobes deep and separated by 

 rather wide notches; thorax unicolored 



Somatochlora (in part) 



— Crenulations on lateral lobes shallow, teeth low; thorax 

 with a dorsal longitudinal dark stripe 



Cordulia (in part) 



33. Lateral spines present on abdominal segments 8 and 9 



34 



— A single small lateral spine present only on abdominal 

 segment 9 or none 35 



34. Mentum with distal margin crenulate; abdominal seg- 

 ments 4 to 7 with dorsal tufts of long hair (fig. 4: lira) 



Orthemis 



— Mentum with distal margin entire, evenly contoured; 

 abdominal segments 4 to 7 not as above (fig. 4:11ft) 



Libellula (in part) 



35. Mental setae 5-11, lateral setae 8-10. . .Belonia (in part) 



— Mental setae 12-16, lateral setae 10-12 



Tarnetrum (in part) 



36. Anal appendages long, slender and needle-pointed; 

 lateral spines of segments 8 and 9 long and curved 

 toward meson, those on segment 8 at least as long as 

 middorsal length of segment 9 (fig. 4: 13;-A;) 37 



— Anal appendages short and heavy, not projected into 

 a long needlepoint; lateral spines on segments 8 and 

 9 flat and straight, those on 8 not as long as middorsal 

 length of segment 9 ■ 38 



37. Lateral spines of abdominal segment 8 but slightly 

 shorter than those of segment 9 (fig. 4:13;'); lateral 

 spines of segment 9 reaching tips of anal appendages, 

 crenulations of distal margin of lateral lobe shallow 

 (fig. 4:11;') Tramea 



— Lateral spines of abdominal segment 8 only one-third 

 size of those of segment 9; lateral spines of segment 

 9 not reaching tips of anal appendages (fig. 4:13A:); 



crenulations of distal margin of lateral lobe deep (fig. 

 4: Hi) Pantala 



38. Lateral setae 6 or 7; lateral anal appendages more 

 than half as long as the inferiors 39 



— Lateral setae usually 9 to 16, sometimes as few as 6; 

 lateral anal appendages half or less than half as long 

 as inferiors 40 



39. Lateral setae 6; mental setae 9 to 11; inferior and 

 superior anal appendages subequal in length 



Nannothemis 



— Lateral setae 7; mental setae about 14; inferior anal 

 appendages longer than superior appendage 



Cordulia (in part) 



40. Lateral spines absent or vestigial on abdominal seg- 

 ment 8 Tarnetrum (in part) 



— Lateral spines present on abdominal segment 8 41 



41. Superior abdominal appendages nearly as long as the 

 inferiors (mainly northern North America) 



Leucorrhinia (in part) 



— Superior abdominal appendages usually much shorter 

 than the inferiors (mainly southern North America) 



42 



42. Lateral spines of abdominal segments 8 and 9 subequal 

 in length 43 



— Lateral spines of abdominal segment 8 about half as 

 long as those of 9; lateral spine of 9 equal to or greater 

 than the middorsal length of segment 9 (figs. 4:llg; 

 4: 13t) Pachydiplax 



43. Lateral spines of abdominal segment 8 approximately 

 half as long as segment. 9 middorsally; some species 

 with prominent bunches of setae present on the dorsum 

 of abdominal segments 4 to 9 Erythrodiplax 



— Lateral spines of abdominal segment 8 nearly as long 

 as segment 9 middorsally; without prominent bunches 

 of setae as described above Micrathyria 



Subfamily MACROMIINAE 



This is a small group containing large, actively flying, 

 brown or blackish dragonflies marked with yellow. 

 They fly high, forage widely, and are very difficult 

 to capture. The naiads have a short, flat, almost 

 circular abdomen, an erect horn on the front of the 

 head, and long legs with long simple claws (fig. 4:36). 

 They live sprawled in the silt of bare areas awaiting 

 their prey. Only two genera, Macromia and Didymops, 

 occur in the United States; the latter is restricted 

 to the East. 



Genus Macromia Rambur, 1862 



Most of the species of this group in the United States 

 occur in the area east of the Mississippi River. 

 However, two are found along the Pacific Coast. 

 Macromia magnifica McLachlan 1874, occurs from 

 British Columbia south to California and Arizona 

 (fig. 4:35). Kennedy (1915, pp. 313-322) studied this 

 species in Washington. He states: "the male Macro- 

 mias were usually found patrolling the larger pools 

 or sometimes a patrol would include two or three of 

 the shorter pools. Seldom were more than three or 

 four males seen at any one time, and each male's 

 beat was rarely over three hundred feet long. The 

 flight was very swift, ordinarily about two feet above 

 the surface of the water and straight down the middle 

 of the pools or, on the broader pools, up one side 

 and down the other. For speed few dragonflies can 



