1900] NTOMOLOOICAL SOCIETY. 



oyster- shell bark-louse does, is safer than one that hibernates. What then gives the San 

 Jose Scale its pre-eminence among its brethren as a plant destroyer 1 



First, it is the difference between addition and multiplication. A single brood of 600 

 is left far behind by a three or four- generation multiplication of even 50 or 60 In 

 Ontario the over -wintered San Jose females begin bringing forth their young about the 

 20th of June. If by the 15th of July each of these over-wintered ones has produced 30 

 females, these are by the the latter part of August ready to produce say 50 each (the 

 later mid-summer broods are said to number 200 to 300 females from each mother) 

 giving a total of 1,500, and each of these 1,500 by the early part of October is multiply- 

 ing by 50, totalling for the single season, in Ontario, a progeny of 75,000 females from 

 each individual female that survived the winter. 



It is probable with us that there are three full generations in a year. The posdble 

 ratio of multiplication is probably nearer 100 than 50. (It is said to be between 200 

 and 300 in the latitude of Washington). A ratio of 100 for three generations would 

 give a total of a million. On trees in certain c mditions and of varieties that have resistant 

 bark, probably only a small proportion effect a connection with the sap channels neces- 

 sary for them to complete their life cycle. There is pietty good evidence that a suscept- 

 ible young tree may be overrun and literally sucked to death in three years. On the 

 other hand, the increase of the insect on trees of a susceptible kind has in some cases 

 been very slow. Mr. Honner, Amherstburg, testified that on a young peach tree in his 

 orchard the scale had been most certainly established three years and yet in that time it 

 had spread over but a small part of the tree. 



Secondly, the comparative activity of the larvae and their plumpness at birth 

 enables them to scurry around a considerable distance and to subsist a relatively long 

 time before they perish for lack of food. 



Third, its lack of fastidiousness in the flavor of its nourishment. Trees, shrubs, 

 herbs, foliage, fruit and roots are neither common nor unclean to it. Mr. John Gordon, 

 of Guilds, whose story of his efforts to save his orchard from the officers of the law, was 

 truly pathetic, has spent time and effort without stint in studying and experimenting 

 upon the insects in his neighbors' orchards since bis own was burned. He showed Mr. 

 J. H. Smith, B.A., and me, examples of the settlement of the insect and the secreticn of 

 its scale on fruit of watermelon, root of carrot, fruit of squash, leaves of poison ivy,, 

 garden phlox, high- brush cranberry, and heme rocallis. Besides some of the above he bad 

 artificially inoculated mulberry, basswood, blue beech, red beech, ironwood and elm. We 

 found on September fourth and fifth, breeding females on hemp, pitch forks, rhubarb, 

 burdock, horse-radish, erect door weed, oriental polygonum, hedge mustard, turtle- head, 

 nettle, touch-me-not, potato, white ash, willow, nine-bark, rose, elm, basswood, currant. 



The almost continuous running of the larvae, owing to the fact that they are pro- 

 duced singly over a period of several days, offers the means of their distribution by nest- 

 ing birds, strong winds, horses and workmen engaged in the orchard, and fruit har- 

 vesters. 



The desirability, nay the necessity, of checking, eradicating or controlling an insect 

 so fecund, so omnivorous and so destructive as the San Jose Scale is at once impressed 

 by a knowledge of its habits and capabilities. The usual restriction of animal life to its 

 peculiar faunal zone makes some biologists hope that in our latitude this insect, even if 

 let alone, could not become so destructive as in the latitude of Maryland. The extreme 

 severity of the winter of 1899 proves that prolonged zero temperature, while it may 

 weaken and check it, will not eradicate it. Its allies on our fruit trees are usually held 

 in check by parasitic insects. In the trip just referred to, Mr, J. H. Smith and I were 

 shown two trees the worst infested I ever saw with Chionaspis. Here and there were 

 groups of the spinulous sloughs of Chilocorus. The owner informed us that there had 

 been a great many more of those, but he had brushed them off and killed them. As 

 frequently happens in insect fighting, he was spending his t fforts in killing his allies. 

 In one sample of Putnam's scale that I found on hickory, nearly every shield was perfor- 

 ated and its contents devoured by some insect. 



