MONOGRAPH OF THE NORTH AMERICAN SPECIES OF 

 DERAEOCORJS ( HETEROPTERA; MIRIDAE)^ 



By Harry H. Knight 



The genus Deraeocoris now includes all those species which have 

 been described under Camptobrochis. Largely through the labors of 

 Renter and Poppius the genus is now known to have a world-wide dis- 

 tribution, ninety-three species and forty-three varieties being listed 

 from parts other than the Nearctic region. In the present paper the 

 writer has been able to recognize fifty-four species and twenty-two vari- 

 eties from North America, of which D. ruber (Linn.) is common to 

 both Nearctic and Palearctic regions, making a total of one hundred 

 and forty-six species and sixty-two varieties from the world. Thirty- 

 seven species and twenty varieties are herewith described as new. 



Very little has been published regarding the life history and econ- 

 omy of these insects and in fact the species have been very imperfectly 

 known. The writer has given special attention to the genus Deraeocoris 

 during six seasons of collecting, and as a result, has been able to asso- 

 ciate with definite host plants all but two of the known eastern species 

 as well as certain of those found in the southwestern states. In 

 several instances this relation appears to be more dependent on the 

 predaceous habits of the bugs which feed largely on the aphids 

 found on particular hosts, rather than the sap from the plant. In 

 fact the writer has not detected a single case where the bugs have 

 fed on the foliage of a plant and produced the characteristic leaf-bug 

 injury which is always to be seen on plants infested by true leaf- 

 feeders. The general scarcity of these insects as compared with leaf- 

 feeding species is only another indication of their predatory habits, 

 for predaceous forms never attain great abundance except sporadically 

 in favored spots. 



In the case of several species of Deraeocoris, if nymphs or adults 

 are caged with succulent growth of the host plant, the bugs manage 

 to live on sap alone but appear to prefer plant-lice or other small 

 soft-bodied insects when such are available. Dr. W. H. Wellhouse 

 has reared a specimen of D. fasciolus to the adult stage, the bug feed- 

 ing only on the foliage of Crataegus, altho he found in rearing other 

 specimens that aphids were fed upon when obtainable. The writer 

 has found that Deraeocoris aphidiphagus feeds on Schizoncura amcr- 

 icaiia Riley, wdiile D. nitenatHS feeds upon Schizoneura lanigera (of 



iPublishert. with the aiiprovnl of the Dirertnr. as Tiipcr .\o. li.lC) of the .Tonnial 

 Series of the Minnesota AurieuUnral Ex|ierinient Station. 



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