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NEW YORK STATE MUSEUM 



were also observed at the Rural cemetery near Albany and at Bath-on- 

 Hudson. These peculiar structures are made by the nymphs bringing up 

 pellets of earth and depositing them about the mouths of their galleries. 

 Mr Lander observed one repairing its injured chamber. There have been 

 a number of theories advanced to account for these peculiar structures, 

 but as they were built under such very diverse conditions, no explanation 

 appears to be entirely satisfactory. 



Jlap shuniiis the distrilmtion of the hro<,ds of the 17 ye 

 Dep't Agric. Div. Ent. Bui. 14, n. s. 1898 



(After Marlatt, U. S. 



Description. The perfect insect may be easily recognized by its black 

 body and the bright red eyes, and the red veined wings, in connection with 

 plate II, figure 17. A smaller variety, described by Dr Fisher as 

 T i b i c e n c a s s i n i i, occurs in connection with the large form. 



Distribution. The general distribution of the 1 7 year broods is graphi- 

 cally represented in the accompanying map prepared by Dr C. L. Marlatt. 

 It will be seen, in connection with the one showing the distribution of the 

 broods of the 13 year race, that these latter overlap those having a longer 

 developmental period only to a limited extent. 



