510 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 14 



The inhabitants of the nest numbered 2090. Of these there were 294 queens, 

 771 males, and 1025 workers. In the lower two stories there were still a large number 

 of cells containing immature queens. The other nest was taken on August 23. 

 While much smaller than the one just described, it nevertheless, consisted of six 

 stories. The population numbered 146, consisting of 142 workers, 3 males, and one 

 queen. 



W. J. Baerg, 

 Fayetteville, Arkansas. 



Artificial Production of Tipburn. Experiments conducted at the Iowa Experi- 

 ment Station during the past season have proven that Empoasca mali, the potato 

 leafhopper, is a very important factor in the production of tip- or hopperburn of 

 potato. In July solutions were made by crushing a large number of these insects 

 in both the mature and immature stages in sterile water. Small amounts of these 

 solutions were injected into the leaves by various instruments, such as hypodermic 

 needle and dissecting needle, and in every case within 24 hours a lesion was produced 

 at the point of inoculation showing that these insects possess a toxic principle. 

 Difficulty was experienced in getting large amounts of the solution into leaf tissue 

 by these methods but in a few cases enough was injected to produce an injury decided- 

 ly similar to, if not identical with tipburn. Bvu-ning was produced where the extract 

 was made from crushed adults. In another series of experiments when the young were 

 crushed in a leaf abrasion a small but distinct lesion was produced after 24 hours, 

 the tissue dying and turning brown at these points. When the e.xtract made from 

 crushed young was drawn up into the leaf by the natural transpiration of the plant, 

 burning resulted that was similar to tipburn. In the latter experiments leaves 

 were placed with their cut stems in the leafhopper extract. Solutions made by 

 macerating tipburned leaf tissue in distilled sterilized water were injected into leaves 

 by using a hypodermic needle. No injury resulted from these tests. Leaves 

 inoculated with water alone failed to show injury and when dilute acids or alkalies 

 were injected, the leaves wilted and then turned brown, a condition not comparable 

 to tipburn. The above tests show that the potato leafhopper in both the young 

 and adult stages does contain a toxic principle and that when enough of this is 

 artificially injected into the leaf, tipburn results. 



F. A. Fenton and I. L. Ressler 



Iowa Experiment Station 



Ames, Iowa. 



NotesonaBombylidParasiteandaPolyhedralDiseaseof the Southern Grass Worm, 

 Laphygma frugiperda. — These notes are based on field observations made at Agri- 

 cultural College, Mississippi and on records from several series of larvae collected in 

 the field and reared in the laboratory simultaneously with the field observations. The 

 Southern Grass Worm was very abundant in Mississippi during the summer of 1920 

 and offered an excellent opportunity for study of the parasites of which it is a host. 



During the summer of 1920, two agencies of natural control were found in operation 

 against the Southern Grass Worm, Laphygma frugiperda. One was a Bombylid 

 parasite and the other a polyhedral disease, probably identical with one mentioned 

 by Chapman and Glaser in the Journal of Economic Entomology Vol. 8, Feb., 

 1915. 



The Bombylid was determined as Anthrax liicifer Fabr. by C. T. Greene of the 

 U. S. Bureau of Entomology. The adult, a cloudy- winged, medium-sized bee-fly 

 was observed to be very numerous during the late summer and early fall months. 



