Report of the State Entomologist. 237 



Althougli so mucli has been written of this common insect, yet 

 there are jDortions of its history which demand further study, for 

 example, the extent to which it is double-brooded. 



Is it Double-brooded in the State of New York ? 



Prof. J. H. Comstock, in his Eeport on Scale Insects, contained in 

 his Report of the Entomologist of the U. S. Department of Agriculture, for. 

 the year 1880, in writing of this insect, which he regards as the 

 Mytilaspis pomorum of Bouche, states that " there is but a single gen- 

 eration each year in the north, where the eggs hatch in the latter part 

 of May, or early in June, and two generations in the south." 



All of our entomological writers upon the insect have united, I 

 believe, in this opinion, with the exception of Dr. Harris, who has 

 given this as a summary of its life history: 



The eggs begin to hatch about the twenty-fifth of May, and finish aborft 

 the tenth of June. ****** j_^ about ten days the young 

 become stationary, and early in June throw out a quantity of bluish-white 

 down, soon after which their transformations are completed, and the 

 females become fertile, and deposit their eggs. These, it seems, are 

 hatched in the course of the summer, and the young come to their 

 growth and provide for a new brood before the ensuing wintei'. 

 (Insects Injurious to Vegetation, 1862, p. 253.) 



Prof. Eiley has had the insect reported to him as double-brooded 

 in Wright county, in the southern part of Missouri, and has written 

 further upon this subject, as follows: 



In Mississippi I know that there are two generations each year, as I 

 have received the second brood hatching about the first of Septem- 

 ber. Dr. Harris, years ago, asserted [?, see above, " it seems "J that 

 there were, at least [?] two broods of this apple-tree bark-louse each 

 year, and, though he was evidently in error, so far as his own joar- 

 ticular State (Massachusetts) was concerned, and has been severely 

 berated for this statement by subsequent writers, yet it finally appears 

 that his language is not so very wide of the mark. {Fifth Report on 

 the Insects of Missouri, 1873, pp. 79-80.) 



Not having made special study of this insect at any time, it would 

 not be proper to say that, as a rule, it has two generations a year in 

 the State of New York, and that Dr. Harris was probably correct 

 in his statement regarding it in Massachusetts; but it certainly is 

 double-brooded in New York as far north as Albany in some seasons. 

 The following is the evidence upon which this assertion is based: 



In a communication made by me to the Country Gentleman of Feb- 

 ruary 1, 1877, I stated: " Some terminal twigs of a pear tree growing 

 in a garden in Albany, were recently brought to my notice, upon 

 which the scales of A. conchiformis extended to the extreme tip of the 

 new growth of the year. Accompanying these were some pears taken 



