THE CANADIAN ENTOMOLOGIST, 167 



3. Upper sector of ihe arculus arising from its upper end ; /. e., 



the part of the arculus above the sectors shorter than the part 

 below them Lant/ius, gen. nov. 



Upper sector of arculus arising from its middle ; /. e., the part 

 of the arculus above the sectors longer than the part below 

 them , ^. 



4. Hind femora with 5 to 7 long spines intermixed with smaller 



ones Dromogompkus, Selys. 



Hind femora with numerous shorter spines j. 



5. Ninth abdominal segment a little longer than Slh. Segments 7, 



8 and 9 very little enlarged 6 



Ninth abdominal segment not longer, generally shorter, than the 

 8th ; segments 7-9 more or less enlarged .... Gomphus, Leach. 



6. Dorsum of thorax pale with darker stripes ; 8th abdominal segment 



cut obliquely at apex, longer on the dorsum than at the sides, 

 abdominal appendages of $ hardly longer than the 10th seg- 

 ment Orcus, gen. nov. 



Dorsum of thorax dark with paler stripes ; 8th abdominal seg- 

 ment not longer on the dorsum than at the sides ; abdominal 

 appendages of" the 9 at least one half longer than the loth 

 segment Stylurus, gen. nov. 



Nymphs of four of our N. American Gomphine genera remain 

 to be discovered. Tachaptryx and Dromogomphus of the eastern U. 

 S., Gomphoides of Texas and Odogomphus of California. I venture 

 now a preliminary table for our known nymphs. Doubtless many 

 modifications of it will be necessary as the unknown nympiis still 

 largely in the majority are discovered. 



Table for Gomphine Nymphs 



I. Wing-cases strongly divergent * 3. 



Wing-cases laid parallel along the back ^. 



*This will not apply to gaping extrrid' in which originally parallel wing- 

 cases have been forced apart 



