444 Report of the Entomologists op the 



scales will be found to present the appearance shown in Plate 

 XIX, fig. 1, which is from a photograph of an infested apple twig, 

 natural size. It will be observed that although differing in shape, 

 being longer and narrow^er, the scales bear a slight resemblance 

 to an ojster-shell, hence the name. If one or two of these scales 

 are turned over [Fig. 2.] they will be found to be well filled with 

 creamy white eggs. If, however, the eggs are not observed until 

 nearly ready to hatch they will have turned to a dark reddish- 

 brown color. There are usually between forty and fifty, although 

 the number may vary greatly. We have found as few as thirty 

 and more than sixty under different scales. The shriveled body 

 of the female scale will be found occupying a portion of the 

 smaller end. The eggs vary in shape as shown at Fig. 3, which is 

 from a photomicrograph showing a number of the eggs greatly 

 enlarged, but in general appearance slightly resemble miniature 

 hens' eggs. They also vary in size^ but from a number of meas- 

 urements we found that an egg of average size would measure 

 about 0.3 mm. by 0.18 mm. 



The eggs remain protected by the scales all winter. In this 

 climate most of them have hatched by the first of June. In some 

 seasons they hatch earlier than others. Last year many newly 

 hatched lice were observed on apple trees in the vicinity of the 

 Station as early as May 7. 



The newly hatched lice are very small, measuring only about 

 0.4 mm. in length and half as broad. A good idea of their shape 

 is given in Plate XX, fig. 1, c. Their bodies are nearly flat and 

 light yellow in color. They wander about for a short time, vary- 

 ing from a few hours to a day or more, finally settling down, 

 most of them on the new growth, where they begin to suck the 

 sap by means of their sharp, thread-like mouth parts. They 

 probably never go to the leaves and only one or two cases have 

 been reported where the scales were found on the fruit. It is 

 probable that when once settled on the bark the females never 

 move. 



The scales grow rapidly and by the latter part of July are 

 mature. Most of the scales grow to havei the appearance already 



