98 ASSOCIATION OF ECONOMIC ENTOMOLOGISTS. 



In the case of a species of Isosoma seriously affecting timothy, we 

 have almost a parallel case, as we rear with it an undescribed species 

 of AVebsterellus from New England to Tennessee and west to the 

 Mississippi River, the absence of Isosoma apparently increasing and 

 decreasing in proportion to the abundance of the parasite. As the 

 pest decreases the yield of timothy seed from 5 to 18 per cent, and 

 injures the hay crop as well, it will be seen that the parasite is, to a 

 certain extent, saving the property of the farmer. 



Take as another illustration the army worm {Heliophila U7iipuncta 

 Ha AY.), which we know does not occur destructively in the same 

 locality two years in succession. Anj^one who has watched an out- 

 break has hardly failed to observe the havoc wrought by one or more 

 species of tachinid flies. I remember distinctly an outbreak years ago 

 m Indiana, where immediately after the outbreak of the army worm 

 the fields were literally swarming with these flies, and the hum of 

 their flight, as they flew about among the stubble and grasses, 

 reminded me of bees. With a single exception, in the last twenty- 

 five years, I have never observed an outbreak of this pest without 

 these useful insects being present in abundance. 



Perhaps the most serious insect pests of the arid regions, where 

 irrigation is followed by alfalfa culture, are the several species of 

 grasshoppers, and scarcely a year passes that numerous complaints 

 do not come to us of their depredations. One of the most common 

 species involved is Melanoplus diff erentialis Thos. Under date of 

 August 7 a report was received from Fort Laramie, Wyo., stating 

 that large numbers of these grasshoppers were dying and clinging to 

 the alfalfa and weeds, over an area of about 6 acres. The material 

 received Avas a mass of dead, disintegrating, and decaying bodies of 

 this species of grasshopper, thickly populated Avith maggots from 

 AAdiich Sarcopliaga georgina Wied. Avas reared. Clearh^ it Avas this fly 

 that had caused the mortality among the grasshoppers. June C), pre- 

 vious, a similar complaint had been received from Lakin, Kans. In 

 this last case the statement Avas made that in some instances over 

 patches of nearly an acre, in an alfalfa field, the plants Avere literally 

 covered Avith dead grasshoppers. AMiile the grasshopijer problem is 

 not noAv, nor is it likely to be, settled by this species of Sarcophaga, 

 it is clear that the restraining influences of these dipterous parasites 

 ai-e great; and AA'e are not in a position to say Avhat the grasshopper 

 situation might not be if the parasites Avere not present. 



The phenomenon that is most likely to attract the attention of the 

 ordinary farmer is that of cutAvorms being dcA'oured by Calosoma 

 larva?. I judge this to be the case from my OAvn experience in connec- 

 tion with entomological correspondence, as there is hardly a year 

 during Avhich cutAA'orms are es]-)ocially numerous Avhon our attention 

 is not called to the matter by letters from farmers Avho have observed 



