April, '13] MORRILL: EXTOMOLOGICAL PIONEERING 189 



being the principal crops to suffer from these insects. What is per- 

 haps the most interesting species occurs in southeastern Arizona where 

 it is a serious pest of the bean and alfalfa crops. It is one of the ''lub- 

 ber" species (Tccnipoda picticornis), locally known as the "Military 

 grasshopper." It breeds in the desert and feeds upon mesquite until 

 nearly full grown when it overruns cultivated fields, if any are near to 

 the breecHng grounds. A peculiarity of the species habits, affording 

 a convenient means of control, is that the insects climb trees, fence 

 posts and other objects at night, evidently for protection. This habit 

 at once suggests a ready means for trapping the insects or for early 

 morning collections by hand. As bearing upon this grasshoppers 

 need for protection against natural enemies, suggested by the habit 

 mentioned, it should be noted that this strikingly marked species is 

 apparently unpalatable to turkeys. 



Thysanoptera. The citrus thrips (Euthrips citri) is the only nota- 

 ble citrus pest known to occur at the present time in the state. Citrus 

 nursery stock does not appear at all subject to injury by this insect 

 in Arizona as it is in the San Joaquin Valley of California. During 

 the past four seasons only about one fifth of the citrus groves have had 

 fruit sufficiently scarred to warrant remedial measures, but this small 

 proportion has suffered extensiveh^ The average damage varies less 

 from year to year than does the damage in individual groves. With- 

 out any remedial measures or changes in cultural methods, the grove 

 most severely damaged in 1911 produced fruit in 1912 which was prac- 

 tically free from the characteristic surface scarring. 



The flower or grain thrips {Euthrips tritici) appears to be more de- 

 structive to deciduous fruits in the Salt River Valley than in other 

 sections of the country. An instance of injury unusual in its severity 

 has been recorded and illustrated in my second report.^ More or less 

 local damage is occasioned by this pest each year. It seems probable 

 that the abundance of the flower thrips in the Salt River Valley is due 

 to the long breeding season and to the large acreage of alfalfa, in the 

 blooms of which the insect thrives. 



Hemiptera. In many parts of Arizona the blood sucking cone nose 

 (Conorhinus sanguisugus) takes the place of the bed bug as a house- 

 hold pest. In the Salt River Valley it is supposed that the bed bug 

 does not exist. This insect has, however, been forced upon my ob- 

 servation in the Verde Valley at an elevation of about 2,000 feet. The 

 unquestionable thriftiness of the insect at the point where this obser- 

 vation was made confuses any attempt to explain the apparently com- 

 plete absence of the pest in the older and far more densely populated 

 Salt River Valley at elevations a little more than 1,000 feet. Is it 



1 Third Annual Report Arizona Horticultural Commission, pp. 21-23. 

 3 



