U. S. D. A., B. E. Tech. Ser. 20, Pt. IV. F. I. I., May 27, 1911. 



TECHNICAL PAPERS ON MISCELLANEOUS FOREST 



INSECTS. 



IV. STUDIES IN THE SAWFLY GENUS HOPLOCAMPA. 



By S. A. RoHWER, 

 Agent and expert. 



INTRODUCTORY NOTE. 



(By A. D. Hopkins.] 



This second contribution by Mr. Rohwer to technical information on the sawflies, 

 while not treating of species of known economic importance in their relation to forest 

 growth, conforms to our plan of giving in one series of publications the results of 

 the necessary general studies, by a specialist, of the entire group represented by 

 species and genera which are of special economic imi^ortance. This not only gives 

 the economic entomologist a comprehensive view of the whole group, but makes 

 available information on species which may prove to be injurious to indigenous or 

 cultivated plants. 



INTRODUCTION. 



In the Canadian Entomologist" the author has a paper treating 

 the sawfly genus Hoplocampa Hartig through the subgenus Macgil- 

 livrayella Ashmead. The present paper treats the Nearctic species 

 of the subgenus Hoplocampa, inchiding also a description of a new 

 species belonging to the subgenus Macgillivrayella. 



The accompanying map (fig. 10) gives, in general, the distribution 

 of the genus. Macgillivrayella apparently does not occur in the 

 Palaearctic region. In America the species of the genus will probably 

 be found to occur from the Lower Austral Zone to the lower border 

 of the Boreal Zone. 



The species of this genus are small, closely related, and without 

 striking specific characters. The characters used in the following 

 table were found to be reliable, but the saw of the female shoidd be 

 examined when possible. Lacking a large number of males, the 

 male genitalia were not studied, but, judging from the genitalia in 

 other genera of sawflies, they may be expected to possess good specific 



oCan. Ent., vol. 42, pp. 242-244, July, 1910. 



139 



