154 DRAGONFLIES OF NORTH AMERICA 
2  Frons dark with a superior transverse oval yellow spot. Size large, 
(Length: 73 mm:),.0:...15 4,0 see ee diadema, p. 155 
Frons uniformly colored. Size smaller, (length 62 mm.)........ 3. 
3. Face yellowsn. 304 (oes tee ee eee sayi, p. 155 
Face. blackish... heat cad cere) era eens erroneous, p. 155 
4 Abdomen with a mid dorsal line of spots..................... 5. 
Abdomen ‘with lateral.spots..05.4.. 0%) 6 Se ee tke Be 6. 
5° Spots bifid ‘on middle segments: 2/22. 5955.06 dorsalis, p. 156 
Spots spear shaped on middle segments......... obliquus, p. 158 
6 Length of abdomen less than 60° mm... .-" a eee eee a: 
Length of abdomen"65 mm... 0.2... ee fasciatus, p. 158 
7 Asingle pair of lateral spots on each segment. Eyes not contiguous 
ROE PIP RR Reet rare en Nay gee TRA si Ag diastatops, p. 158 
A median and an apical pair of spots on the middle segments. 
FIVER CONTIPUOUS. 05 a)0 0 pis eaten koe Aes ae maculatus, p. 159 
* By C. F. Byers. 
Nymphs* 
1 Segments 8 and 9 without lateral spines.................... 2. 
Segments 8 and 9 with lateral spines...................-.--. 3. 
2 Each division of the bifid middle tooth of the mentum truncate on 
the end, and with a very shallow secondary intendation, followed 
by a straight row of small denticales. Lateral setae 6-7...... 
Mentum with each half of the middle tooth again strongly bifid, 
the lower half being smaller and almost hidden among the hairs 
at its base. No denticles. Lateral setae 5........... diadema. 
3 Lateral spines on 8 and 9 stout, straight, and conspicuous. Teeth 
on the lateral lobes comparatively broad and blunt.......... 4, 
Lateral spines on 8 and 9 small, cylindric and hidden among scurfy 
hairs. Teeth of the lateral lobes long and sharp............. 
ay bettas arbitunits d thid gd Re Sta eres a ie ed ee es maculatus. 
4 Median tooth of the mentum secondarily bifid into two equal 
parts; 2.0. TESTO Sa FCS Ue ee sayi 
Median tooth of the mentum secondarily bifid into two unequal 
parts, the lower being the smaller... .'. ...0..)..2RiE gaa2e 5. 
5 Lateral setae.5. Mental setae 10-11................ diastatops. 
Lateral setae ‘6. “Mental l3.4:..4 4. s220- 2) so eee obliquus. 
The nymphs of erroneous and fasciatus are still (1928) unknown. 
* By C. F. Byers. 
