MATERNAL INDUSTRY: COCOONS OF ORBWEAVERS, 



105 



some cocoons empty, one with spiderlings passed tlie first moult several 

 days, and another with young who had just broken the egg. There was 

 no trace of the bifurcated abdomen upon these younglings. The spider 

 is of a uniform light green color, about the shade of its cocoon. 



Another Orbweaver that makes several cocoons is Epeira basilica. I 

 am indebted to Dr. George Marx, of Washington, for the specimens from 

 which the following studies and drawings have been made, as 

 Cocoon of ^ygH j^g fQj. ^]^g information concerning Basilica's habit of caring 

 „*f, for her eggs. The number of cocoons is five, thus corresponding 



with that of Labyrinthea, and generally with Caudata. Thej' 

 are round, covered on the outside with gray spinningwork, and united by 

 a cordage so stiff that the series stands out like a stick. They arc attached 

 to a triangular patch of yellowish white silk, which is an expansion of a 

 long, glossy, strong linen like cord, composed of many 

 threads, by which the string of egg balls is suspended. 

 (Fig. 98.) 



According to Dr. Marx, whose observations were made 

 at Washington, the string is hung just above the centre 

 of Basilica's peculiar domed snare, and wholly or in part 

 within the dome, as represented at Fig. 99. The mother 

 has position beneath her egg bags, back downward, as 

 is the habit of Orbweavers making horizontal snares. > 



When the cocoon is dissected, it is found to consist, 

 first, of an exterior sac of gray material ; within this is 

 next enclosed a round black case (Fig. 100), four or five 

 millimetres in diameter, having a thin shell of remark- 

 able hardness, in this respect resembling the cocoon of 

 Cornigera. When illuminated and examined under the 

 microscope this egg ball is seen to be composed of yellow 

 silken fibre of exceeding fineness, and so closely woven that, looked at 

 when within its bag, it is quite black. The paper like stiffness of the ball 

 could hardly be caused by even such fine spinning, and I believe that the 

 fibres are smeared with a viscid secretion, which gives them their peculiar 

 stiffness. When this black case is cut open it is seen to contain flossy silk 

 (Fig. 101), which forms the customary wrapping of the eggs and nest of 

 the young spiders. 



The cocoon of Uloborus is about one-fourth inch long, and one-eighth 

 thick. It is drawn out at either pole into a point, and the surface is 

 covered with small pointed or blunted processes. (Fig. 102.) It 

 is made of a pure white silk, quite stiff of texture. Several of 

 these cocoons (I have never found more than three) will be found united 

 together so closely that they appear to be but one object, and not strung 



Fig. 98. Cocoon string 

 and suspension cord 

 of Basilica spider. 



Cocoon. 



See for further debiils Vol. L, Chapter IX., especially page 170, Fig. 15!). 



