MEDIAN NOTCH. A notch in the edge of the pygidium at the pos- 

 terior extremity of the body. This is a very important charac- 

 teristic of Aulacaspis and Phenacaspis. Shown on Plate 4, Fig. i. 



PYGIDIUM. The pygidium is composed of several of the terminal 

 segments of the body which have been transformed and which 

 together form a flattened organ used as a trowel. No definite 

 dividing line between the pygidium and the rest of the body can 

 be designated, but for the purposes of this paper it is consid- 

 ered to extend to the notch just anterior to the fifth group of 

 gland-spines, counting from the median lobes. Fig. 4, on Plate 

 5, is a more or less diagramatic representation of the body of a 

 female insect in this group. The pygidium which extends as 

 far anteriorly as the notch between segments seven and eight is 

 seen to be made up of parts quite similar to the segments of the 

 rest of the body. 



SCALE. The entire shield-like covering of a scale insect, composed 

 in part of secreted matter produced by the insect and in part of 

 exuviae molted from the body and incorporated into it. 



SECOND EXUVIA. See exuvia. 



SPINES. Two spines occur on each side of each of the segments of 

 the pygidium, the one above usually being the larger. These 

 are generally considerably smaller than the gland-spines and 

 have a circle at their base. See Plate 4. Fig. 5 F and G. 



STYLE. A long spine-like appendage at the end of the body of the 

 male Coccid. 



