4 EXPLANATION OF TERMS. 



for specific distinctions. (Plate i., Fig. 4, for types of various spinnerets ; 

 Plate iii., groups of spinnerets of Diaspidince.) 



Spiracles. "Breathing organs:" the orifices in the body of the tracheae or 

 tubes conveying air to the blood. In the Lecanidince they are usually four ; 

 simple circles, near the edge of the body, and with a few strong spiny hairat 

 near them. In the Coccidina they are often numerous. (Plate ii., Fig. 4 ; 

 Plate xx., n.) 



Spiracular spines. Spiny hairs, usually three in number, of which one is rather 

 long, close to the spiracles, in the Lecanidina. 



Stigma, stigmatic spines. Terms sometimes employed for spiracles, &c. 



Tarsus. The fourth joint of the feet, between the tibia and the claw. Its con- 

 sisting of one joint (monomerous) is a distinctive character of the whole 

 family. (Plate i., Fig. 6, ta.; Fig. 7, ta.) 



Test. The waxy, glassy, or horny covering produced through the spinnerets 

 and concealing the insect in many Lecanidince and some Coccidince. In 

 this work it is not applied to the " scale " of Diaspidince, or to cottony secre- 

 tions. 



Thoracic band. An appearance seen on the thoracic region in the male, looking 

 like a broad transverse ribbon. 



Thoracic region, thorax. That part of the female or the male which bears the 

 three pairs of feet, when the feet are present ; or, if the feet are absent, the 

 middle portion of the body, segmented or not. 



Tibia. The third joint of the feet, next the femur. (Plate i., Fig. 6, tl. ; Fig. 

 7, ti.) 



Trachea. Tubes ramifying throughout the body, conveying air to the blood 

 Their orifices are the spiracles. The tracheae, as in other insects, appear as 

 if constructed of a network of fine spiral wires. (Plate ii., Fig. 4 d; Plate 

 xx., n.) 



Trochanter. A small articulation, not a distinct joint (something like a knee-cap) 

 of the feet, between the coxa and the femur. (Plate i., Fig. 6, tr. ; Fig. 

 7, tr.) 



Trimerous. Three-jointed. 



Ventral. On the under-side, the insect being in its proper position. 



