BULLETIN NO. 32, MARCH, 1895. 97 



and a second molt takes place, and we have a covering- which is known 

 as the medial scale, and which either surronnds or extends from one end 

 of the larval scale, according to the species. In the male the form of this 

 scale IS usually very much narrower than in the female, and often ribbed- 

 it IS, also, often markedly of a different color, or pure white, while the 

 female scale is usually darker, or imitates the color of the bark. Thus 

 the sexes are now distinguishable by their scales or shields while the 

 insects, themselves, are also readily distinguished at this stage, the male 

 having transformed to a pupa, with the limbs, feelers and wings fur- 

 shadowed, and the female remaining a mere yellow mass without such 

 organs. 



In the male a third molt takes place under this medial scale, and a 

 delicate two-winged fly with long feelers and a single anal style backs out 

 from the rear end. His color is usually pale, with a reddish or dusky 

 band across the middle of the thorax, and the wings have but two deli- 

 cate veins. The antenn;v are variously jointed, the more common num- 

 ber of joints being eight. In the female scale, on the contrary, there is no 

 particular difference of form after the second molt. She still grows and 

 IS destined to remain underneath her scale, which becomes much larger 

 and forms what is known as the anal sack. Here after a third molt, she 

 becomes fertile and either produces her young alive or lays her eggs.' In 

 either case the young in due time issue from the scale, and begir again 

 the cycle of life, as already related. In those species in which the scah 

 is more or less circular, like the one \\;e are considering, the stages of the 

 scale growth are not so readily separated as in the elongate species which 

 resemble an oyster or a mussel shell. The larval scale is however, usually 

 conspicuous, as a central raised point. 



The different species of the sub-family are distinguished from each 

 other not only by the peculiarities of their scales, which do not always 

 offer trustworthy separating characters, but by the peculiar arrangement 

 of the secretory pores on a darker and more chitinized anal plate, and Ijy 

 the peculiarities of the margin of this plate, especially in the female. 



Our particular San Jose Scale is quite circular in form, very flat and 

 pressed close to the bark. It grows from 1-1(J to 1-S of an inch in diam- 

 eter in the female and about half this size in the male. It has the gen- 

 eral color of the bark and the larval scale in the centre is a slightly 

 raised point varying from yellowish to nearly black in color. It is 

 perhaps, the smallest scale which occurs in Maryland, and is further 

 <3haracterized aud distinguished from all others, which the fruit grower 



