Spi 208 



a larger or smaller number of short, fine tubes ; 

 at the apex of each is the aperture of a silk 

 gland, which lies in the abdomen. These 

 spinning glands may vary considerably in 

 structure even in the same insect, and may give 

 rise to different secretions. (A.S. spinnan.) 



Spinous. — ^Armed with spines. (L. spina, a thorn.) 



Spinous-radiate. — Beset with spines in a circle. 

 (L. spina.) 



Spinulae. — Spinous processes at the base of the tibia 

 in Hymenopterous insects. (L. sjjinula, dimin. 

 of spina, a spine, a thorn.) 



Spinules.^Small, fine, scale-like structures which 

 occur on the thickened veins of the wings of 

 numerous insects. Minute spines. (L.spimda.) 



Spiracles. — Breathing apertures occurring at intervals 

 along the sides of insects, and which communicate 

 with the air tubes or trachew. The number of 

 spiracles is generally eighteen, nine on each side, 

 but the number is not uniform. The names 

 depend wholly on the segment in which they 

 happen to be situated ; ex. the right spiracle of 

 the prothorax is prothoracis spiraculum dextrmn. 

 The spiracles vary greatly in form, position, 

 and number, (L. spintus, breath, from spiro, 

 to breathe.) 



Spiracula antepectoralia. — A pair of spiracles fixed 

 in the membrane that connects the antepectus 

 with the medipectus. (L. spiritus ; ante, before, 

 and pectus, the breast.) 



