12 Oklahoma Agricultural Experiment Station 



ond abdominal segment. The head is withdrawn first, the anten- 

 nae are straightened out and the nymph gradually draws its body 

 from the molted skin. The dorsal spines aid the nymph in break- 

 ing the skin and in pulling itself free from it. The act of molting 

 requires from two to four hours, and a newly molted nymph is 

 creamy-white, not assuming its normal dark brown color for sev- 

 eral hours after it has left the old skin. 



Distinguishing Characters of the Different Stages 



The first stage can always be recognized by its more slender, 

 less flattened appearance, the absence of long, spine-bearing pro- 

 tuberances, and by each spine having a blunt tip which is usually 

 enlarged and rounded. The minute spinules found covering the 

 body surface in the succeeding instars are absent in this stage. 

 But five facets are present in each eye. 



The second stage still has only the one spine on the lateral mar- 

 gin of each of the abdominal segments two to nine, but it now arises 

 from an elongated protuberance instead of a conical base and is 

 pointed, while just inside of this is a trumpet-shaped spine. The 

 body is broader and darker in color. The antennae are still three- 

 segmented, but the lateral margins of the pro and meso-thorax 

 bear two spines on protuberances and a trumpet-shaped spine just 

 inside of these instead of the single blunt spine on a conical base 

 found in instar one. Each eye has six or more facets. 



Ths third stage now has four segments in the antennae, but the 

 wing pads are not developed beyond a faint enlargement. The 

 lateral margins of abdominal segments two to nine have three 

 spines, one on a protuberance, one arising from a conical base, 

 and a trumpet-shaped spine just inside of these. Each eye has 

 fifteen or more facets. 



The fourth stage is easily recognized by the well developed 

 wing pads which are oval in outline and reach to the second ab- 

 dominal segment. The anterior margain of the pronotum is ex- 

 tended forward to the eyes, or slightly over them, while the pos- 

 terior margin is produced into a rounded triangular point or apex 

 at the median line. 



The fifth stage will be known at a glance by the greatly de- 

 veloped wing pads, rather elongated and reaching to the fifth ab- 

 dominal segment. The anterior' margin of the pronotum at the 

 median line is raised and extended a little forward while the pos- 

 terior margain is quite distinctly triangular. The lateral margins 

 of the abdominal segments one, two and three are without spines. 



METHODS OF CONTROL 



Natural Enemies 

 "There are a number of predatory insects which prey upon the 



