Ovisac of female (see fig. 2, p. 124). White, or rarely pale buff. Usually more or less reniform, rarely quite globular or more or less hemispherical; surfacewith well-marked transverse, flutings and sometimes also with faint longitudinal striæ. The waxen plates and mealy secretion of the female are often visible on the exterior, more especially so in the earlier stages of the formation of the ovisac. When quite intact it has a closely felted appearance, but on the least disturbance the material is capable of stretching out into long, viscous, elastic threads interwoven with a granular or mealy secretion, which latter disperses in the form of a little cloud of white smoke.

Length 3–5 mm.; rarely attaining a length of 7 mm.