84 Eighteenth Report State Entomologist of Minxesota — 1920 



There appears to be little doubt that the spines, their form and 

 arrangement on the tibiae, present characters which are correlated 

 directly with a particular type of body structure, the combined ele- 

 ments of which are characteristic of small groups of species, or gen- 

 era. Certainly the tibial spines are not specific in character but must 

 pertain to a higher category. At present any statement regarding the 

 general usefulness of tibial spines for distinguishing genera is of a 

 preliminary nature, but in so far as the writer has carried his investi- 

 gations it would appear that these characters will prove highlv useful. 

 In the Bryocorinae and Cylapinae the spineless character of the tibiae 

 has been emphasized by Renter, but to the writer it appears that the 

 spines, their arrangement, or absence thereof, may be given more ex- 

 tended use. perhaps supplying additional and much needed criteria for 

 distinguishing genera as well as certain larger groups within the 

 family. 



Subfamily DERAEOCORINAE 



The writer would state the essential characters of the subfamily 

 Deraeocorinae to be as follows : 



Arolia very slender, bristle-like, erect, either parallel or only 

 slightly curved, usually inclined slightly forward away from the tar- 

 sus, sometimes apparentlv absent or difiicult to distinguish from the 

 hairs on the tarsus, in the latter case the claws distinctly cleft ; claws 

 usually cleft but if not then the bristle-like arolia are distinct; pseudo- 

 arolia absent. 



In a key to the subfamilies the writer (1918) raised the group 

 Deraeocoraria Van 1). (not Douglas and Scott) to the rank of a sub- 

 family. This seems to be necessary if we are to have a logical and 

 workable classification of the subfamilies based on characters found 

 in the arolia. For a comparison of the structure and form of the 

 arolia for the different subfamilies of Miridae the reader is referred 

 to a plate of drawings by the writer (1918). Mr. Van Duzee (1916) 

 sought to credit his division Deraeocoraria to Douglas and Scott 

 (1865) but it seems to the writer that such a procedure is scarcely 

 permissible in view of the fact that all the species which were included 

 in the Deraeocoridae of Douglas and Scott are now known to belong 

 in genera outside the group in cjuestion. 



Of the genera known to the writer the following are placed in 

 the subfamily Deraeocorinae: Dcracocoris Kirschb.. Kiopicoris Van 

 D.. Dil'loaona Van D.. luirychiU^ptcrcJla Rent.. Ciinatlaii Dist.. and 



