648 
JOURNAL OF ECONOMIC ENTOMOLOGY 
[Vol. 17 
ADIRUS TRIMACULATUS SAY—A ROSE PEST 
By A. B. Champlain, Pennsylanvia Bureau of Plant Industry 
Abstract 
Adirus trimaculatus (Say), a sawfly of the family Cephidae, known as a borer in 
blackberry canes in the larval stage, is definitely identified as the borer doing similar 
damage in rose stems. 
It is suggested that infested portions of plants be removed and destroyed. Ex¬ 
tensive control measures have not been attempted, and there is room for considerable 
investigational work both of a biological and economic nature. 
Larvae of Adirus trimaculatus (Say) are known to be borers in black¬ 
berry canes and in a number of instances have been suspected of being 
a rose pest. At times during the past five years, correspondents of the 
Pennsylvania Bureau of Plant Industry have submitted samples of rose 
twigs and shoots that were injured by borers in the form of whitish 
larvae that tunnel the stems and kill the terminals, with the request for 
identification and remedies. 
In addition to our own provisional identification of this insect as 
Adirus trimaculatus , some of the material was sent to Mr. S. A. Rohwer, 
Specialist in Hymenoptera, at the United States National Museum, 
who replied as follows: “We have received similar larvae from rose on a 
number of occasions, but so far the adult has never been reared and the 
identification is based entirely on the larva, but is supplemented by the 
fact that we do not know any large Cephid other than Adirus which 
could be associated with it.” 
Mr. William Middleton 1 writes concerning the larva: “This species is 
recorded boring in blackberry, while the specimens described was re¬ 
ceived through Dr. F. H. Chittenden’s office as coming from rose.” 
Dr. E. P. Felt 2 mentions that larva as follows: “The reception of a 
horn tail larva, possibly that of Adirus trimaculatus (Say), breeding in 
rose shoots at Woodhaven, was unusual and may mean the introduction 
of a new rose pest.” 
The late John B. Smith, in “The Insects of New Jersey,” records this 
species and comments: “The larva bores in the stems of blackberry 
canes entering at the bottom and eating out the center to the top.” 
This is just the reverse of what actually happens, the larvae work from 
the tips down through the center of the canes. 
The adults of Adirus fly during the latter part of May and through 
June and July in Pennsylvania and on July 12, 1924 the author was for- 
^otes on the larva of some Cephids, Proc. Ent. Soc., Wash. Vol. XIX, P. 177, 
1917. 
N. Y. Report 32, Page 60, 1918. 
