INSECTS OF THE SEASON IX IOWA IX 1893. 



By Herbert Osborx, Sjieeial Agent. 



LETTER OF SUBMITTAL. 



Ames. "Iowa, October 2S, 1S93. 

 Sir: I forward herewith a report on some observations of the season of 1893 

 referring to the general insect attacks of the season, and with more special reference 

 to a few forms that are of unusual interest. Aside from the observations reported 

 here a number of other species have been studied, but full reports can not be pre- 

 sented at this date, and they can be better treated in special papers. 



During the season I have r^epared TTr0 papers, one On the Methods of Combat- 

 ing Insects Affecting Grasses and Forage Plants, and the other On the Treatment 

 of Parasites of Domestic Animals, presented at the meeting of the Association of 

 Economic Entomologists, at Madison, both of which were in large part the results of 

 studies that had been made with reference to the division work. Allow me here to 

 express my thanks for many favors during the year. 

 Very respectfully, yours, 



Herbflt Osborn. 

 C. V. Riley, 



U. S. Entomologist. 



The season of 1893 has been somewhat exceptional in the nature of 

 its insect attacks, a number of species usually inconspicuous becoming 

 seriously abundant and attracting no little attention on the part of cul- 

 tivators. This has been especially true of the clover-hay worm, the 

 wheat-head army worm in some localities, the clover-seed caterpillar, 

 and the horn fly. The first part of the season was rather cold and quite 

 wet, so that insect injury, except that caused by the clover-hay worm 

 in barns and stacks, did not attract attention. The latter part of the 

 season, however, has been quite dry, amounting for a few weeks to a 

 drought, and within this time insects have shown their presence in 

 very destructive numbers. A somewhat detailed statement of the 

 various species will be in order. 



From the conditions present this season it is probable that we will 

 have a pretty large number of grasshoppers another season, unless the 

 occurrence of the blister-beetles and Bombyliid larva?, which destroy 

 the eggs, has been extensive enough to reduce their numbers. 



On the Hatching of the Eggs of the Horse Bot-fly. — On September 19 I 

 obtained a number of eggs of the common horse bot-fly, and from the 

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