128 MONTANA EXPERIMENT STATION. 



season of 1902 and in 1903 the species was commonly seen both on 

 the apple and the elm at Missoula. 



On making inquiry I learned from Mr. C. F. Dallman, proprietor 

 of the Missoula nursery that this insect has at times been so abun- 

 dant on the limbs and trunks of elms as to cause the leaves to 

 wither. From the foregoing it appears that while the insect was 

 originally found on the apple at Missoula it is more particularly a 

 pest of the elm and that on that desirable shade tree it is capable of 

 becoming a serious pest. So far as the notes in this 

 office show, we have, beside this mealy-bug, onlv one serious 

 pest of elms in Montana. This is the aphis which lives on the 

 leaves causing them to curl and become deformed. 



HISTORY OF THE SPECIES. 



Phenacoccus dcanicssi was originally described by Mr. Geo. B, 

 King. Mr. John Dearness collected the original specimens from an 

 old hawthorne tree near London, Ontario. The species has not 

 been heard of since Mr. King's mention of it in Volume 33 of the 

 Canadian Entomologist until this writing. 



A RELATED SPECIES. 



This mealy-bug is a member of the family of bugs scientifically 

 i-.nown as Coccidac. To this family belong the true scale insects, 

 soft scales, cottony cushion scale, the cochineal insect, and the lac 

 msect. Altogether they form a very large and important group, 

 there being upward of one-thousand five hundred species known to 

 science. Another species in the same genus as the one that is the 

 subject of this paper, has been injurious on maples in the eastern 

 p.art of the United States. This species {P. accricola King) has 

 about three broods during the year and does its damage by sucking 

 the juices out of the leaves. The cottony masses on the under side 

 of the leaves are conspicuous objects and where the insects become 

 abundant they cause the leaves to become yellowish and sickly or 

 drop off prematurely. The wmter is passed by the young nymphs 

 which secrete themselves in the crevices of the bark and there re- 

 main dormant. In the spring becoming active again they crawl 

 to the leaves. 



