192 



THE UNIVERSITY SCIENCE BULLETIN. 



reeled downward (really three segments). The tarsi are all 1-segmented 

 and end in two claws. The tarsi of the hind legs are fringed with hairs. 

 The middle femora are furnished on their caudo-ventral margins with 

 two strong bristles set upon elevations. 



Second Instar. 

 The presence of the tuft and fringe of hairs on the ventral abdominal 

 carina is the chief addition over that of the previous stage. The rear 

 margins of the middle femora are now equipped with three strong bristles 

 and there is a suggestion of the tooth or spine that becomes prominent 

 in the succeeding instar. Antennae 3-segmented. First segment short, 

 disc-like, second somewhat globose and third elongate. 



Third Instar. 



The caudal margin of the mesothoracic femur now carries a well- 

 developed tooth as well as the three stout spines noted in the second 

 instar. Tibia and tarsus of hind leg now fringed with hairs — wing- 

 pads as in figure 4, plate XX. 



Fourth Instar. 

 The middle femora now bear very stout processes in the line of the 

 caudal row of spines. A series of short processes on the ventral side 

 of this segment take the place of minute rugosities of the previous instar. 



Fifth Instar. 



The tooth or strong spine on the mesothoracic tibia is now extremely 

 wide at its base. The limbs are stouter than previously and the vdng- 

 pads now have the position shown in figure 4 of plate XX. 



In the table below the measurements are in millimeters and based 

 on reared material. The adults are certainly smaller than those taken 

 in Ithaca, N. Y., though practically the same as specimens from nature 

 in Kansas. These figures are intended to help in determining an instar. 

 The series measured is not large enough for purposes of generalization. 



TABLE OF MEASUREMENTS. 



General Notes on Development. There are certain constants of struc- 

 ture that are carried through all the nymphal instars. The mesothoracic 



