duction to my report for last year. In several cabbage fields in 

 Central Illinois, I saw, in August and September, the work of this 

 larva arrested and the insect itself almost exterminated by an out- 

 break of this disease. 



An epidemic extremely similar to the above, possibly identical with 

 it, and not impossibly derived directly from it, has prevailed exten- 

 sively during the season among the silk worms of Illinois, having, 

 for instance, almost completely destroyed a lot of these worms at the 

 Industrial University which were being reared for experimental pur- 

 poses. I have this season successfully cultivated the virus of this 

 disease and applied it to the destruction of other insects. 



The FOREST TENT CATERPILLAR, an Outbreak of which species oc- 

 curred last year in Southern Illinois, was again seen in the same re- 

 gion this season, but in number so greatly reduced as to inflict little if 

 any definite injury. The condition and fate of examples collected 

 by us in Southern Illinois this year and kept in breeding cages 

 until they perished, confirmed my supposition of a destructive con- 

 tagious disease among them, apparently the principal cause of their 

 disappearance last year. This was one of the diseases known as 

 muscardine, similar to that of the silk worm occasioned by the well- 

 known fungus Botrytis ha><siana. 



Probably the most notable entomological event of the year was 

 the extraordinary abundance of the maple bark louse (Pulvinaria 

 innumerahilis), which species occurred in destructive numbers through- 

 out the State, at least from Chicago to Shelbyville, and probably 

 also farther south. Notes upon the life history, and details of ex- 

 periments upon this species with insecticides, will be found upon 

 another page. 



The CHERRY SLUG {Selandrla cerasi) continued abundant this year, 

 extending its ravages farther to the south than the year before. It 

 was extremely abundant in Central Illinois, at least as far south as 

 Bloomington, many trees being nearly defoliated by it. 



The APPLE LEAP skeletonizer {Pempelia liammondi) and the lesser 

 apple leaf roller {Tcras malivorana) were each more abundant, 

 locally, in Central Illinois, than the year before, and continued their 

 injuries in nurseries until a later date, in some cases almost wholly 

 preventing advance in growth of young nursery stock. 



The GRAPE POMACE FLY, the larvae of which abound everywhere in 

 rotten apples and in old pomace at the cider mills, was this year 

 reported as extremely injurious to grapes in Western Illinois. 

 Another grape pest, well known in Europe, but not hitherto reported 

 in America, (the grape phytoptus), was discovered by us this season 

 in Illinois, infesting certain of the native varieties. The Grape 

 Phylloxera, concerning whose status in Illinois I have received this 

 season several inquiries from foreign consuls, has maintained about its 

 usual average during the present year, doing occasional damage to 

 those varieties especially susceptible to it, but producing little or no 

 effect upon the total yield of the vineyards of the State. 



