222 



(2) A submergence of 40 to 50 days in winter is required, and even where the water 

 is allowed to remain during the whole season the vineyard does not suffer. I should 

 consider this very doubtful. 



(3) A vineyard should never be inundated for a longer period ~than two days in 

 summer or during growth ; and, though these brief inundations at that season affect 

 only the few lice near the surface and are by no means essential, they are neverthe- 

 less important auxiliaries to the more thorough fall or winter submersion, as they 

 destroy the few lice which are always invading a vineyard in infested districts. 

 These summer inundations will be necessary only after the winged insects begin to 

 appear, and three or four, each lasting less than two days, made between the middle 

 of July and the fall of the leaf, will effect the end desired. 



(4) Au embankment should be made around the vineyard in order that the water 

 may evaporate and permeate the earth, but not run off and carry away any nutritive 

 properties of the soil . 



The varied success which has attended the different attempts to rout the enemy by 

 inundation is owing to the lack of thoroughness in mauy of them. The ground must 

 be thoroughly soaked for a sufficient length of time. Temporary irrigation does 

 not accomplish the end, for the reason that it does not reach all the lice, and does 

 not break up the numerous air bubbles which form in the soil and prevent the drown- 

 ing of many of the insects. (Sixth Report Insects of Missouri.) 



Too much in fact can not be said of tbe advantages of a system of 

 irrigation in fighting many insect pests. 



A good instance occurred in our experience in the spring of 1879, 

 when the Army Worm appeared in great force upon a large grass plan- 

 tation near Portsmouth, Ya. The plantation was divided into sections 

 by irrigating ditches, and it was only necessary to turn on the water to 

 isolate a badly infested section and to devote it to rolling, fire, or some 

 other means of destruction, preventing ready spread to other sections. 

 In the same way rice planters have a ready means of fighting insect 

 pests at hand. 



Other insects might be particularized, but the general statement that 

 from the stand-point of the economic entomologist irrigation in general 

 is a great help in fighting insect pests, and from the marked illustration of 

 the great good accomplished by the reclamation of the arid regions in 

 connection with the damage done by the Eocky Mountain locust it will 

 probably be considered that further elaboration is unnecessary. 



Respectfully submitted, May 13, 1889. 



NOTE ON THE 0VIP0SITI0N AND EMBRYONIC DEVELOPMENT OF 

 XIPHIDIUM ENSIFERUM, Scud. 



By William M. Wheeler, Milwaukee, Wis. 



Though the Orthoptera have received more attention from students 

 of insect embryology than any other natural order of Hexapoda, there 

 still remain several families which, owing to the difficulty of procuring 

 sufficient material, have not been studied. We possess monographs, 

 more or less complete, on members of the Gryllid, Acridiid, and Blat- 



