OF THE STATE ENTOMOLOGIST. 79 



" 111 1S60 I got from a neighbor two sprouts (winter variety). They 

 did well for a year or two, when I noticed the insects on them. In 

 1869 I cut and burned them, and set 75 young trees on the same land. 

 In 1871 I noticed that the insect had again made its appearance on 

 my young trees, commencing on trees nearest the old stumps. They 

 spread very rai3idly, and increased very fast, and my orchard, once 

 the finest in this part of the country, is now well-nigh ruined. The 

 trees stop growing, and the fruit rots. I know of no other trees in 

 this vicinity infested with the lice." 



Judging from the specimens sent, the lice are not in the most 

 thrifty condition, for few eggs were found that had not been injured 

 by mites ; and there were evidences that some little Chalcid, and 

 perhaps the one described further on, had been at work upon them. 



Is this occurrence so far south, of what we have had good reason 

 to consider a comparatively northern insect, to be looked upon also 

 as exceptional, or will the insect be found, upon investigation, more 

 generally spread through the Southern States? These are questions 

 to which satisfactory reply is, at present, impossible. From all I can 

 learn, there is nothing exceptional in the country, either around 

 Carthage or Waynesborough ; and we may conclude that the bark-lice 

 will thrive in any parts of Georgia and Mississippi, or of the other 

 Southern States. It is an interesting fact, however, as I learn from 

 elaborate meteorological data furnished by Mr. Merchant, and cov- 

 ering a period of 25 years, that the mean temperature of the months 

 of May - October, inclusive; is, at Natchez, Mississippi, lower than 

 that of the same months at St. Louis while, as every one knows, the 

 other months have there a much higher mean temperature than here. 

 It is possible, therefore, that the great height which the thermometer 

 reaches in the latitude of St. Louis, is prejudicial to the Oyster-shell 

 Bark-louse, and precludes its flourishing in this latitude, while it lives 

 and thrives to the north and south of us. At least, I can now give no 

 other explanation for the peculiar geographical distribution of the 

 species. 



ITS SPREAD WESTWARD. 



It has already obtained a foothold in several orcharls around 

 Lawrence, Kansas, having spread from trees originally brought from 

 Ohio. 



BOTH SINGLE AND DOUBLE-BROODED. 



Not the least interesting feature of the southern range of our 

 Bark-louse is its double-broodedness there. In Wright county, Mo., 

 though the young hatch only a month earlier than in North Illinois — 

 or about the first of May — it is nevertheless double-brooded, according 

 to Mr. Palmer; and in Mississippi I know there are two generations 

 each year, as I have received the second brood hatching about the 

 first of September. Dr. Harris, years ago, asserted that there were at 



