THE GENESIS OF SNAKES. 



347 



of Mater 

 nity. 



and Tubeweavers. The same is true of the Saltigrades, who persistently- 

 live in tubes ; of the Laterigrades, who occasionaly form them ; and of the 

 Citigrades and Tunnelweavers, who make silk lined 

 tubular burrows in the ground. 



Among the causes that would lead directly from a 

 simple lineweaving to a tubeweaving habit are the ma- 

 ternal function and instinct. The mother seeks retire- 

 ment when tlie time of ovipositing draws near. 

 ^^^^^?^f Beneath some ledge, or leaf, or stone, or twig, 

 or other convenient shelter, she takes refuge, 

 and there remains until the last act of ma- 

 ternal care. The very continuance in one place would 

 naturally lead to the formation of a rudimentary nest 

 in the manner just explained. The mother's promi)t- 

 ings to protect lier progeny by overspinning the eggs 

 would lead almost inevitably, in many cases, to her- ^^^ 33^ The cocooning nest 

 self sharing the provided shelter, or extending or of a Laterigrade spider, 



n . • • i /> 1 1 m Philodromus. 



adaptmg it tor her own benent. 



How natural is such a step appears from the fact that such spiders as 

 the Laterigrades, that never (or but rarely) use any sort of snare or shelter, 



resort to a tubular cell for the protection of their eggs 

 and young, and dwell within it themselves during the 



hatching season. (Fig. 338.) So, also, Ly- 

 Lateri- cosids, which habitually wander in the open 

 ^^ ^^ in pursuit of i)rey, when the time for co- 

 Lycosids nooning comes make a burrow or nest in 



the ground or ])eneath a rock, which they 

 silk line and use as a domicile. Thus, also, Dolo- 

 medes, which is persistently nestless and webless in 

 ordinary habits, is drawn by maternal instincts to spin 

 among the leaves, or in like situation, one of the 

 most com})lete nests that can ho found in tlio wliole 

 rang(^ of arancad sjiimiingwork. 



Having thus pin'sued the line of analogy from 

 the Lineweaving to the Tubeweaving species, we may 



return upon our covirse for a moment to 

 Analog-y trace the analogies between the Lineweaving 

 Between .j,j,| Orbweaving species. Already, in a pre- 



^^'^^' ceding chapter (Chapter YIU.), l have fully 



weavers .,, , ^ , t, ,. 1 1 -^ r ^ ■ r\ C 



and Orb- dhistrated the peculiar habit of certain Orb- 

 weavers, weavers to combine with tlieir typical or- 

 l)i(ular snare the typical retitelarian snare 

 Conspicuous examples of tliis are Ei)eira labyrin- 



FiG. 339. The cocooninp nest 

 of Dolomedes sexpunctatus. 



of the Lineweavers. 



thea, Epeira triaranea, and most of the species belonging to the genus 



