82 Eighteenth Report State Entomologist of Minnesota — 1920 



Other genera of the subfamily Deraeocorinae, Camptobrochis would 

 appear to be only a part of the large genus Deraeocoris. 



In an effort to settle the question regarding the proper name to 

 use for our Nearctic species the writer has made an extended study 

 of the possibilities for generic characters. In this work the one most 

 constant character which appears to be distinctive throughout the 

 large genus Deraeocoris is the arrangement of the spines on the front 

 tibiae. In following the tibial characters it became necessary to refer 

 elsewhere two species which have been recognized as aberrant in the 

 genus, and with their removal a more satisfactory diagnosis may 

 be drawn for Deraeocoris. 



The Tibial Comb 



In making a survey for available characters in the Miridae the 

 writer discovered an interesting structure in the form of a comb at 

 the distal end of the front tibiae. To this the writer applies the name 

 tibial comb for it is very similar to the comb-like structures well 

 known on the legs of certain Hymenoptera. For the Miridae there 

 appears to be no mention in the literature of such a structure on the 

 tibia, the small size and inconspicuous nature of the comb doubtless 

 accounting for this. The tibial comb lies at the distal end of the 

 fore tibia and in the same plane as the anterior face, there being no 

 dififerences between the sexes. The comb is composed of a single row 

 of very fine, closely placed, translucent spine-like teeth, set on the 

 very apical margin of the tibia, usually bounded dorsally by one or 

 more thick dark colored spines and ventrally in the same manner, the 

 exact number and arrangement being different for each genus within 

 a related group (PI. IX). The front tibia is always more or less 

 flattened on the anterior face near apex and usually very distinctly 

 sulcate, these modifications being well adapted for cleaning both ros- 

 trum and antennae. On a few occasions the writer has observed living- 

 bugs cleaning the rostrum and antennae by applying the front feet, 

 one on each side of the member and combing from base toward apex; 

 in such cleaning operations the tibial comb undoubtedly has an im- 

 portant function. The tibial comb is fully developed in all the fourth 

 and fifth stage nymphs which have been examined. A cursory exam- 

 ination of species in other families indicates that the tibial comb is 

 present in all the Heteroptera having well developed antennae. In 

 certain species of Reduviidae the comb is situated somewhat before 

 the apex of the tibia. 



