THE INSECT RECORD FOR I902 73 



lobes of the calyx are wide open, as shown in the right hand 

 apple of the picture on the title page. When the growth of 

 the fruit has caused these lobes to close, as shown in the middle 

 apple of the same picture, it is too late to spray to advantage. 

 A rather coarse spray which shall drive the poison into these 

 open lobes is also believed to be better than a fine misty one. 



One of the most notable entomological events of the season 

 of 1902 was the sudden and nearly complete disappearance of 

 the Black Squash Bug 1 — a pest that was extraordinarily 

 abundant in 1901. While cucurbitaceous plants of all sorts 

 were attacked and to a great extent destroyed in the last-named 

 year, in 1902 practically no damage appears to have been done 

 in any part of the state, and the insects were very much less 

 common than usual. Reports from other states indicate a 

 similar disappearance over a wide territory. 



We made a careful study of this squash bug in 1901, the 

 more important results of which are recorded in Bulletin 89 

 of this station. We found the percentage of parasitism to be 

 too small to account for the disappearance of the pest, and no 

 other natural enemies are known to be efficient enough to ex- 

 plain the fact. The only satisfactory explanation that I can 

 think of is that the insects were killed by the weather condi- 

 tions in the winter of i90i-'o2. 



Another disappearance almost as marked as that of the 

 Squash Bug, though less generally noticed on account of the 

 small size of the insects, was that of the Apple Leaf-hopper. 

 As noted in the Record for that year, in 1901 this little insect 

 was extraordinarily and destructively abundant, causing the 

 leaves of whole apple orchards to appear spotted and sickly. 

 In 1902, however, the Leaf-hopper did no noticeable damage. 



No injury was reported from any part of the state as done 

 by the Forest Tent Caterpillar 2 or the Spiny Elm Cater- 

 pillar 3 , these insects still remaining much below the normal 

 limit in their numbers. The Choke-Cherry Tent-maker 4 

 also continued much less abundant than usual, its conspicuous 



x Anasa tristis De Geer. 

 *Clisiocampa d is stria Harris, 

 s Vanessa antiopa Linnaeus. 

 *Caccecia cerasivorana Fitch. 



