170 AMERICAN SPIDERS AND THEIR SPINNINGWORK. 
extended upward from the exterior of the dome to the inclosing and sup- 
porting labyrinth of crossed lines. Evidently the little engineer had com- 
pleted the work, so well begun in the depression of the edges of her orb, 
by elevating the central part through the same method of applying force, 
but in an opposite direction. So well had the power been graduated that 
the proportions of the dome were beautifully preserved. 
We have thus traced the analogy between the spinningwork of this 
species of Orbweavers and that of Lineweayers in these several particulars: 
_. First, in the dome shaped snare and dwelling place, which cor- 
Spinning responds with that made by a species of the Retitelarian genus 
work ; 3 : : : : 
Analo. Linyphia. Second, in the mass of intersecting lines placed around 
gies. and above the dome, which is the characteristic web of the Retite- 
larian genus Theridium and of many other genera. ‘Third, in the 
sheet like curtain beneath the dome, which in form resembles the thinly 
Fic. 159. Position of Basilica’s web after the horizontal orb has been transformed. The meshed 
structure is only indicated. The original plane of the orb is shown at f. 
sheeted web of many species of Linyphia, as, for example, L. costata; and 
which in both position and form corresponds with the underlying curtain 
or dish of L. communis and L. marginata. 
Thus, Epeira basilica is seen to possess all the leading characteristics of 
the principal families of the Retitelariee, namely, (1) the maze of crossed 
lines, and (2) the sheeted web in exact detail, and (3) the dome shaped 
web in outline. It also possesses the chief characteristic of the Orbitelarie, 
namely, the geometric web, or radiating lines regularly crossed by concentrics. 
Moreover, it combines in its dome structure the vertical and horizontal forms 
which are the prevailing ones in the orb of its congeners. The Basilica 
spider may, therefore, be regarded as well nigh, if not completely, bridging 
the space between the spinning economy of these two great tribes of the 
Aranee. 
