376 REPORT OF THE COMMISSIONERS OF 



ened by repeated losses of their foliage is a serious matter. The extent of this 

 drain is hardly appreciated till one observes the damp sidewalks, which even the 

 heat of summer cannot dry, and the blackening fungus covering broad leaf expanses 

 and indicating an equal amount of moisture, — all of which is drawn by these little 

 creatures from the struggling trees. On bright sunny days in June it is very easy 

 to see the exudations of these bark lice falling in showers from infested trees. 



Introduction and distribution. This insect, like many of our worst insect pests, 

 is an introduced species. It was first brought to notice in this country in 1884 by 

 Mr Charles Fremd, of Rye, Westchester county, N. Y., who complained that thou- 

 sands of elms in his nursery were infested. This species was probably accidentally 

 imported several years previous to its discovery. It has now become established at 

 a number of points in the Union, having been recorded from Vermont, Massachu- 

 setts, District of Columbia, Michigan, Nevada and California, besides localities in 

 New York state. It is known to occur on Long Island and in a number of places 

 along the Hudson river north to Greenwich, and it has been received from Ogdens- 

 burg, St. Lawrence county. Thus, if this pest has not already attained a general 

 distribution throughout the state, it is only a question of time before that will occur. 



Description. The adult females are by far the most conspicuous form of this 

 insect. They may be seen clustered along the under side of the smaller limbs, 

 usually along a crack or crevice in the bark, and presenting a general resemblance to 

 a growth of lichens. The full grown, viviparous females are about T V of an inch long 

 just before giving birth to their young, oval in outline and with slightly pointed 

 extremities (Plate 3, figures 16, 16a). Each is surrounded with a white, woolly 

 secretion, which also extends partly over the insect and thus renders its segmenta- 

 tion more apparent. 



The young are yellowish specks and may easily be recognized as they move 

 over the younger limbs and leaves (Plate 3, figure 15). They have an elongated, 

 oval form, rounded anteriorly and tapering posteriorly to a pair of pointed pro- 

 cesses, each bearing a long and a short seta. The body segments are marked by 

 lateral spines and there is a row of six around the anterior border of the head and 

 an irregular row down the middle of the back. The young soon become darker and 

 finally assume a yellowish-red color. The dorsum becomes covered with spiny, wax 

 secreting processes, and the general form of the young larva is retained (Plate 3, fig- 

 ures 10, 13). The antenna of the female before impregnation is composed like that 

 of the young, of six subequal segments, the second and third being the longest and 

 the fourth and fifth shortest. The antenna of the immature male has six nearly 

 equal segments and a longer seventh. 



