4 ODONATA. 



Very similar to Gomphus vulgatissimus, differs in having less promi- 

 nent tubercles on occiput. Denticulation of palpi deeper. Wing-cases 

 reaching 4th segment. Abdomen considerably narrower, more rounded 

 above ; 8th and 9th segments with tubercles on dorsal line, lateral spines 

 on 9th longer than 10th segment, which is very short ; 9th segment a 

 little longer than 8th. Anal appendices a little shorter than in G. 

 vulgatissimus. Hind legs extending to 8th segment only. 



5. Gomphus species. 

 Plate II., fig. 5. 



Nympha full grown, 24 mm. long, 6 mm. broad, similar to G. vulgatissi- 

 mus. Locality: Massachusetts. Coll. Mus. Comp. Zool., and Coll. Hagen. 



Body tapering less abruptly. Head with flat spots instead of tuber- 

 cles on occiput. Wing-cases reaching middle of 4th segment. Legs 

 rather more slender. Dorsal hooks on segments 6 to 9 ; on the other 

 segments rudimentary. Lateral spines on segments 7 to 9 ; 9th seg- 

 ment longer than 8th, with lateral spines nearly as long as 10th, which 

 segment is rather longer than in G. vulgatissimus. 



There is another, from same collection, younger, 21 mm. long. 



6. Gomphus species. 

 Plate II., fig. 6, b. 



Nympha. Length, 24 mm. ; breadth, 7 mm. 



Locality : Pole Creek, W. Texas. Coll. Hagen. 



Body flat. Head flat, cordate. Eyes rather prominent. Ocelli de- 

 veloped. Part behind eyes rounded. Antenna?, two basal joints globu- 

 lar, 2d smallest, 3d elongated and enlarged, 4th small, rudimentary. 

 Whole head granulated. Mask extending to fore legs, length greater 

 than breadth, moderately channelled in middle, middle third somewhat 

 produced, with comb of bristles. Palpi enlarged and rounded at ends, 

 very finely denticulated. Movable hooks long and sharp. Wing-cases 

 extending to middle of 3d segment. Legs strong. Hind legs more 

 separated at base. Middle and fore legs of nearly equal size, strong, 

 formed for burrowing. Femora and tibiae arcuated. Tibia? with 

 strongly marked end spine ; tarsi 2-jointed ; claws sharp. Hind legs 

 reaching 9th segment ; tarsi 3-jointed. Abdomen flat, tapering. Dor- 

 sal hooks on all segments except 10th. Lateral spines on segments 7 

 to 9. Segments of nearly equal length. Lateral spines of 9th much 



