20 BULLETIN 256, U. S. DEPARTMENT OF AGRICULTURE. 



the course of life, and in the orchard under normal conditions they 

 probably deposit more than the maximum number here given, since 

 on one occasion 133 eggs, showing advanced development, were re- 

 moved from the ovisac of a female which had not oviposited during 

 her entire life in captivity. The number of eggs laid at one time 

 varied from 3 to 28. The adults live from three to three and one- 

 half months, and are present in the orchard almost continuously 

 from the middle of August to the middle of November. Adults lived 

 in screen cages from 85 to 111 days. 



Seasonal History. 



Most of the eggs of this species are deposited during September and 

 October, and all eggs secured from females in captivity in 1911 and 

 1912 were deposited between September 4 and October 29. The 

 eggs hatching the following spring, the nymphs make their appearance 

 about the first of May. They reach the maximum abundance be- 

 tween May 15 and July 15 and will seldom be seen after the middle of 

 August. Adults are most numerous during the period from August 

 15 to October 15; they are scarce in November and rare in December, 

 finally disappearing entirely in January. 



CONTROL OF KATYDIDS ON ORANGES. 



Several methods have been suggested for the control of katydids on 

 oranges, among which the following have been found to be imprac- 

 tical: Destroying the nymphs by hand; gathering by hand and 

 destroying the eggs; poisoning by the use of trap crops or by poisoned 

 baits. It would be extremely difficult, if not impossible, to find any 

 large percentage of eggs or nymphs, and the method would certainly 

 prove too slow and tedious. The katydids can not be attracted from 

 the fruit and foliage of the orange by any crop or bait while such an 

 abundance of food so much to their liking is always at hand. Unless 

 practically forced to quit the orange tree, they spend their entire lives 

 upon the tree on which they are born. 



- SPRAYING EXPERIMENTS. 



Spraying with arsenicals is generally considered to be impractical 

 for the control of grasshoppers and locusts because of the large dose 

 necessary to kill these robust insects and the difficulty of applying 

 such a dose evenly and with safety to the trees. These objections 

 would doubtless hold with the citrus katydids if the spraying were 

 done after the insects had reached an advanced nymphal or the adult 

 stage. They do not hold, however, when the trees are properly 

 sprayed while the insects are still largely in the first, second, or third 

 nymphal instars. 



