SPINULES AND HAIR-SCALES 



197 



and not into a tube, as Landois supposed. Spuler describes a sort 

 of double sac structure or follicle (Schupperibaly} which receives the 

 hollow pedicel of the scale. This was originally (1860) observed by 

 F. J. Carl Mayer, but more fully examined by Spuler (Fig. 228) 

 though not detected by A. G. Mayer. 



Spinules, hair-scales, hair-fields, and androconia. Besides the 

 scales, fine spinules occur on the thickened veins of the wings of 





FIG. 226. Portion of a cross-section through the pupal wing of Danais pleosippus, about six 

 days before emergence: sg, scale; cta.nl, wing-meinbrane ; cl.frm, formative cell of the scale; 

 mbr.pr, ground-membrane ; fbr.h'drm, hypodermal fibres of pupal wings. A, portion of a longi- 

 tudinal section through the 'pupal wing, eight or nine days before emergence ; prc, processes of 

 young hypodermis scales. This and Figs. 223-225 after Mayer. 



the Blattidse, where they resemble fir-cones ; also in the Perlidse, in 

 the Trichoptera, and in the more generalized Lepidoptera (Microp- 

 terygidae and Hepialidse), occur, as indicated by Spuler, delicate 

 chitinous hollow spinules scarcely one-tenth as long as, and more 

 numerous than, the scales, which sometimes form what he calls 

 "Haftfelds," or holding areas. These spinules have also been 

 noticed by Kellogg, and by myself in Micropteryx ; Kellogg, and 

 also Spuler, have observed them in certain Trichoptera (Hydro- 



