298 ENTOMOLOGICAL NEWS. [November, 



was not full of midge larvae. The trees set very heavily, and early in June 

 I made a most careful search; not for insects, but for pears that were not 

 infested, and absolutely failed to find a single one that was sound. One 

 tree, not more than thirty feet from the edge of the exempt orchard, was 

 literally loaded with fruit, all of it infested. That not more of the midges 

 came to this good orchard is at first sight surprising, but it is perhaps ex- 

 plainable by the fact that last year there was only a small crop of Law- 

 rence pears and that comparatively few midges matured, and those that 

 did so, found an abundance of opportunity to oviposit, so there was no 

 need for them to migrate. This enormous multiplication induced an 

 earnest appeal to the owner of the infested orchard, was persuaded, when 

 the matter was properly presented, to consent to a stripping of the trees, 

 and for two days bushels upon bushels of the young fruit were picked and 

 destroyed; with it of course the midge larvae contained in them. For 

 purposes of experiment I collected perhaps two quarts of the infested 

 pears. These I divided into eight parts as nearly equal as it was possible 

 to get them; care being taken that each lot should, as nearly as possible, 

 resemble the other in the proportionate number of large and small ex- 

 amples, so as to make each lot a fair sample of the whole. Eight fruit 

 jars were half filled with sand and one lot of the infested pears was placed 

 in each jar. The pears were left there for several weeks, being moistened 

 very occasionally to prevent their hardening and drying, and to facilitate 

 the escape of the midge larvae. Late in June, or early in July, the pears 

 in each jar were carefully sorted over, those that had been fully abandoned 

 by the larvae were thrown away, and those that had not broken open or 

 decayed, were cut to enable the insects to escape from them. Early in 

 August the jars were again overhauled, the ground was found full of larvae, 

 and the now completely abandoned pears were thrown away. Two of 

 the jars were left as checks; two others of the jars received a small quan- 

 tity of nitrate of soda; two others an equal quantity of muriate of potash, 

 and two others a somewhat larger quantity of kainit. In each case the 

 dry fertilizer was sprinkled upon the top of the ground; in the one in 

 what would be a light top dressing; in the other in what would be a liberal 

 application of the same fertilizer on a commercial scale. In each case it 

 was intended that natural conditions should be resembled as nearly as 

 possible. A very small quantity of water, just sufficient to moisten the 

 surface of the soil was added after the fertilizers had been applied, and at 

 intervals during the season small quantities of water were added, just 

 sufficient in each case to moisten the soil. On October 6th, all except 

 one of the check jars were examined. In each case the entire contents 

 of the jar was dumped into a large, shallow pan, to which water was 

 added, and the sand was carefully washed. It proved to be easy to sepa- 

 rate out all foreign material from the sand, and this foreign material was 

 simply the midge larvae or the cocoons made by them. In each case all 

 the insect contents of each jar were put into a vial, the vials all of exactly 

 the same size, in order to compare by bulk the number of specimens. 



