1'roceedings, 1914. 37 



its centres of infestation one year following another. One .year it will be very 

 troublesome on the Delta, and another year at Agassiz, and so ou. It is therefore 

 with the puriiose of detailing the centres of infestation, such as I hare notes on, each 

 succeeding year, to demonstrate the trend and the migrations of these insects, that 

 is the main reason for this paper. 



In 1890 the caterpillars were very prevalent in the Lower Fraser Valley from 

 Agassiz down to the mouth of the Fraser Valley; that is, the entire valley was 

 severely troubled by the presence of these insects. 



In 1S07 the caterpillars were again present throughout the valley, with a slight 

 iui-rease in numbers in the Chilliwack District and a lessening or easing off through 

 the Delta. 



In 1.S9S Chilliwack. Langley, and Surrey were the centres of infestation, while 

 there was a lessening in abundance on the north shore of the Fraser and a practical 

 disappearance ou the immediate coast. 



In 1S99 only a few caterpillars were observed in the valley this year, which 

 indicated that some disease coupled with its own insect parasites had been active 

 (luring the fall of 1898. This remarkable disapi)earance of the insect in injurious 

 numbers is worthy of note, for this condition of almost freedom continued until 1907. 

 a period of nearly ten years. I do not wish to advance any theories ou these happen- 

 ings, as they are beyond my ken, but I merely wish to record the dates and the year.-: 

 when these caterpillars were troublesome to the farmer. The points or centres of 

 infestation already mentioned 'were severe infestations, the caterpillars causing 

 .serious injury to the foliage of orchard as well as to ornamental or forest trees. 



In 1908 the caterpillars appeared again during the summer, evidently from eggs 

 laid the iircvious fall. They evidently had come up from the State of Washington 

 from the south, as they were very destructive from the International Boundary-line 

 through the Delta, Surrey, and Langley Districts. They appeared in slight numbers 

 in the Chilliwack and Agassiz'Districts and only lightly on the north shore of the 

 Fraser. This 1908 Infestation was severe and covered a great deal of territory, and 

 when it is considered that in the year previous (1907) there was a practical freedom, 

 with the exception of a slight infestation somewhat heavier than elsewhere in that 

 year about Maple Itidge on the north shore of the river and at Langley ou the south, 

 it seems the more remarkable. 



In 1909 the infestation had increased to a great extent, about the same territory 

 as in 1908 being still the worst infested. It may be practically said that the infesta- 

 tion was doubled at each point as compared with the year previous. 



In 1910 the moths had evidently flown up the river towards Lytton, for during 

 this summer a few caterpillars were observetl at this point. Hope, Ruby Creek. 

 Agassiz, Chilliwack, Harrison River, and Dewdney were evidently the centres of 

 infestation, while there was also a continuance, but possibly to a lesser degree, in 

 the Langley, Surrey, and Boundary Di.stricts. It was apparent the infestation was 

 moving eastward. 



In 1911 only a few caterpillars renntined at Chilliwack and Surrey. I have no 

 notes on the country east up the river, hut judging from the migration route it would 

 appear possible that the Lytton District- was the centre of infestation. 



In 1912 only a few remained up tlu' river, while the Fraser Valley was fairly 

 free. 



In 1913 there were no caterpillars in tlie Lower Fntser Valley, but the country 

 about the I'emlierton Jleadows and as far up the Fraser River Valley as CJuesnel 

 were very severely infested. An account of this infestation I have included in 

 another part of this bulletin imder the heading of " Insects for the Year." 



This present winter (1914) I have been on the search for egg-nnisses. but I Inivc 

 lieeu forced to consider that we are not likely to be again visited by the caterpillars 

 this coming season. If there is such a thing as recurring seas<ms, and any delinitc 

 r\ile on which Mother Nature works, it may be i)ossiblo that we will not again be 

 trnulilcd liv a serious outbreak, such as Ihe ones I have uu'ntioued. for possibly teii 



