loOb INSIiCTS ETC. INJURIOUS TO VARIOUS CROPS 



version into a pupa. The skin of the larva only shrank a few days before 

 •it burst. It is pointed out that these changes were never observed by the 

 Author, though he studied thousands of larvae. More precise indications 

 on this question were given by vSchEidter, who found that the larvae which 

 have attained complete maturity show deep black oval spots above the eyes, 

 visible to the naked eye, which represent the eyes of the future pupa ; they 

 are called " Puppenaugen " (pupal eyes ). In the months of April, Maj' and 

 June 1913, on the basis of this character there were examined 11 800 lar- 

 vae from 8 different stands, and the number of those ready for transforma- 

 tion into pupae determined. It was found that this criterion is only partly 

 correct. "Pupal eyes" do not appear only before conversion into pupal 

 form, but as early as the pre\nous autumn or summer. The larvae were 

 found with pupal eyes in the month of August 1913. 



This fact is important in practice, as by its aid it may be determined in 

 the autumn whether or not there will be a great flight of Lyda in the fol- 

 lowing spring. 



While observing the evolution of larvae into pupae the writer also 

 ascertained the number of pupae in the above stands. Within a few weeks 

 alone he found great variations in the number, which variations oc- 

 curred at all points at the same time. The cause is probably the w^eather, 

 which exerts an influence on the transformation. A high temperature in 

 April is found to favour the formation of pupae. 



The perfect insect emerges very early from the soil, the emergence ap- 

 pearing also to be related to the weather. If the weather is rainy and foggy, 

 only a small number of adult insects are found, while on fine days they come 

 out in large numbers. According to the writer mating generally takes 

 place on the ground, on the leaves of Gramineae and very rarely in the 

 crown of the tree. 



With regard to Lyda control commenced in the forest of Roggenburg, 

 the Author remarks as follows ; glue bands at a height of about 5 feet 

 above the groimd proved very successful at the beginning of flight. The 

 female insects rarely reach the summit flying, most of them climbing up the 

 tree. 



Tater on, when the weather allowed the insects to emerge in large 

 numbers, and the ovaries of the females were full of eggs, the females tra- 

 versed the band of glue without being captured. This observation is in 

 contradiction with those of many investigators, and thereiore the studies 

 should be continued. The writer also made experiments with fly-papers 

 and obtained excellent results. The high cost of this method of control 

 however prevented him from repeating the experiments on a large scale. 

 In any case they showed that a substance must be used with the proper- 

 ties of the glue used for catching flies if it is desired to obtain good results 

 with glued bands or strips for controlling Lyda. 



Alfredo Rugceri, gerente responsabile. 



