87 



season. From all of the information we have at present obtained it 

 would seem as though outbreaks of this pest may l)e largely prevented 

 in this way. and it has been demonstrated by actual experimentation 

 that the insect can be destroyed by spraying the plants along the 

 edges of the fields when they first begin to show the effects of attack 

 with a mixture of 1 pound of whale-oil soap dissolved in 8 gallons of 

 water. 



Although this thrips in Russia is a tobacco insect, it invariabh^ 

 declined to feed upon tobacco with us, and held strictl}^ to the onion. 

 Lest I might be mistaken in regard to the species, specimens were sub- 

 mitted to Mr. Pergande, who compared them with Russian specimens, 

 and informed me that there was no doubt but that we were dealing 

 with the true TliTipfi tabacl. 



In early April, 1897, the writer found adults of Myochrous denticollis 

 attacking young corn in the fields in Tensas Parish, La! No "seriDtis 

 injury, however, seemed to follow, and this, so far as known to me, is 

 the only published record of the food habits of the insect. On June 

 2 Mr. Alva Agee, of Cheshire, Gallia County, reported that the insect 

 had attacked the young corn in his neighborhood, apparently working 

 serious injury. Specimens of the beetles were sent with the complaint. 

 On June 4 my assistant, Mr. Newell, was sent to the locality to inves- 

 tigate the outbreak, and found that the territory infested comprised all 

 the cornfields contained in an area of 3 miles square. In all cases the 

 infested cornfields were upon land which had been the year previous 

 either in pasture or lying out wild. A very few of lie beetles were 

 found upon blue grass. In the in sectary, however, they seemed to 

 prefer corn first, next timothy, and lastly the blue grass. In this case 

 the beetles were not observed to feed upon the stems of the corn plant 

 below the surface of the ground, but upon the leaves and leaf sheaths. 

 The feeding was done during the morning and evening, or upon cloud}^ 

 days. When there were drifting clouds the beetles would come out 

 and feed while the sun was under a cloud, but go back into their hiding 

 places in the ground when the sun came out bright and warm. ' Dur- 

 ing the day they were observed to hide in the crevices of the soil and 

 in the loose dirt near the corn plants, from 2 to 15 being found in close 

 proximity to the different hills. The beetles are densely punctate on 

 the back, and these cavities retain more or less of the soil, which gives 

 the beetles the same general color as the ground. They seem to have 

 no inclination whatever to fly, but run quite rapidly. One female that 

 was dissected contained 5 yellow, cylindrical eggs, estimated to be 

 about 1 mm. in length. 



It would therefore appear that the insect is one that feeds upon, and 

 probably its larv^ also develops upon grass. In the latter stage it 

 appears to be of subterranean habits. At present no remedial or pre- 

 ventive measures have been tried. 



