6 Annals Entomological Society of America [Vol. V, 
are supposed to secrete the viscid silk. Correlated with the 
presence of a cribellum is the presence of a comb of bristles on 
the metatarsus of the hind legs for manipulating this silk. 
It should be noted in this connection that viscid silk is 
produced by at least three different sets of glands in different 
families of spiders. By the lobed glands in the Theridtide, as 
already described; by the cribellum glands in the Cribellate; 
and in the orb-weavers to be described later it is obviously 
produced by some other glands, as these spiders possess neither 
the lobed glands nor the cribellum glands. Apparently this 
very useful product has arisen independently at least three 
times within the order Araneida. 
The viscid silk of the Cribellate is a band-like structure 
whose form is partly determined by the combing action of the 
calamistrum. I have, therefore, termed it the hackled band. 
The hackled band of one of the Dictynide, that of Amauro- 
bius may be taken as an example. This band consists of two 
parts; first, a supporting structure, which may be termed the 
warp; and second the viscid silk, which may be termed the woof. 
The warp consists of four elastic threads, two of which are 
straight and two are curled. The woof is a narrow sheet of 
viscid silk, the edges of which are undulating. It is probable 
that each undulation was produced by a stroke of the cribellum. 
While it is probable that the viscid silk, is spun from the 
cribellum glands, the threads constituting the warp are doubtless 
spun from spinning tubes situated on the spinnerets. 
Turning to the webs of the spiders that spin a hackled band, 
we find great differences in the extent to which this band is 
used and also in the nature of the web of which it forms a part. 
It is easy to arrange these webs in a series which suggests a 
possible course of their evolution. 
In the Dictynide is to be found the simpler types in this 
series. Here the foundation of the web is irregular, its form 
depending very largely upon the situation in which it is built. 
The following will serve as examples: 
Dictyna foliacea spins an irregular web of dry silk across the 
concavity of a leaf; and mingled with the dry threads are 
strands of viscid silk that have no regularity of arrangement. 
Dictyna volucripes spins an irregular web of dry silk upon 
the stems of herbaceous plants; and upon this foundation 
stretches its hackled band in comparatively regular ladder-like 
