 | Thaddeus William Harris, Massachusetts. Zoological and Botanical Survey - 1841 - 484 páginas
...white color, and in having an elevated ridge passing down the middle. The minute oval dark-colored scales on one of the ends of these white cases are the skins of the lice while * Kongl. Vetenskapa Academ. Nya Handlingar. they were in the young or larva state, and the white shells... | |
 | Cuthbert William Johnson - 1844 - 1210 páginas
...of the males, and differ from those of the females not only in size and shape, but also in Кмпг of a purer white colour, and in having an elevated...lice while they were in the young or larva state, arid the white shells are probably formed in the same way as the down which eiudes from the bodies... | |
 | Thaddeus William Harris - 1852 - 536 páginas
...passing down the middle. The • Kongl. Vetenskaps Academ. Nya Haudlingar. minute oval dark-colored scales on one of the ends of these white cases are...according to the sex, and becoming membranous after it ia formed. Not having seen these insects in a living state, I have not been able to trace their progress,... | |
 | United States. Congress. House - 846 páginas
...ridge passing down the middle. The minute oval dark-colored scales on the ends of these white cases arc the skins of the lice while they were in the young or larva state." The white scales themselves are probably a secretion, which becomes dry and hard by the contact of... | |
 | 1866 - 280 páginas
...— that the scales of this American species are not composed of the dried body of the female, but "in the same way as the down which exudes from the bodies of other bark-lice." In the middle of November there may often be seen on such twigs as are infested by these scales, very... | |
 | United States. Department of Agriculture - 1881 - 1028 páginas
...explanation of their nature and probable mode of formation as follows : The minute oval dark-colored scales on one of the ends of these white cases are...as the down which exudes from the bodies of other bark lice, but which in these assume a regular shape, varying according to the sex and becoming membranous... | |
 | 1881 - 968 páginas
...explanation of their nature and probable mode of formation as follows: The minute oval dark-colored scales on one of the ends of these white cases are...as the down, which exudes from the bodies of other bark lice, but which in these assume a regular shape, varying according to the sex and becoming membranous... | |
 | United States. Department of Agriculture - 1881 - 988 páginas
...explanation of their nature and probable mode of formation as follows : The minute oval dark-colored scales on one of the ends of these white cases are...as the down which exudes from the bodies of other bark lice, but which in these assume a regular shape, varying according to the sex and becoming membranous... | |
 | Thaddeus William Harris - 1862 - 694 páginas
...white color, and in having an elevated ridge passing down the middle. The minute oval dark-colored scales on one of the ends of these white cases are...bark-lice, but which in these assumes a regular shape, varving according to the sex, and becoming membranous after it is formed. Not having seen these insects... | |
 | 1914 - 1368 páginas
...explanation of their nature and probable mode of formation as follows: " The minute oval dark-colored scales on one of the ends of these white cases are...as the down which exudes from the bodies of other bark lice, but which in these assume a regular shape, varying according to the sex and becoming membranous... | |
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... the insects themselves were not studied by Dr. Harris. The description of the scales is remarkable as containing an explanation of their nature and probable mode of formation as follows : The minute oval dark-colored scales on one of the ends of these... 
