MATERNAL INSTINCTS : MOTHERHOOD. 189 



in the single cocoon of other species. The Labyrinth si)ider laj's from 

 sixty to eighty eggs. The Tailed sfjider about the same. The Bitid spider 

 an aggregate of one hundred to one hundred and fifty in all her cocoons. 

 There is a marked difference in tlie number of eggs contained in the sev- 

 eral cocoons in one brood or cocoon string, as though the female issued an 

 unequal number of eggs at the various periods of ovipositing. 



In tribes other than Orbweavers, the various species show the same 

 differences in the number of eggs contained within their cocoons ; for ex- 

 ample, Tegenaria medicinalis has about sixty eggs; Agalena naivia, a hun- 

 dred or more ; Dysdera bicolor, twenty to thirty. Walckenaer reports Aga- 

 lena labyrinthea to contain sixty eggs ; Tegenaria domestica from sixty to 

 one hundred and eighty ; Dolomedes mirabilis, one hundred to one hun- 

 dred and sixty ; Lycosa narbonensis, five to six hundred ; Lycosa agrestis, 

 one hundred and eighty. Dysdera hombergii (Staveley) lays from twenty 

 to thirty eggs. 



It perhaps may be said, as a general rule, that the number of eggs 

 deposited bj' any species corresponds with the size thereof. Thus we have 



seen that our large Argiope will lay as many as twenty-two hun- 

 ize o cli-ed eggs. Westring counted eight hundred eggs in a cocoon 



of Epeira quadrata;^ Epeira diademata will lay as high as eight 

 hundred eggs. Both of these are large species. The great tarantula, My- 

 gale blondii, deposits as many as three thousand eggs. On the contrary, 

 we find such a diminutive Saltigrade species as Synagales picata laying 

 but three eggs, while Phidippus morsitans, one of the largest of the Salti- 

 grades, lays one hundred and eighty eggs, thus being one of the most fer- 

 tile species.^ The Lineweaver Theridium variegatum has six eggs in her 

 cocoon. Oonops pulcher makes several cocoons, and deposits two eggs in 

 each one.^ The cave spider Anthrobia mammouthia lays from two to five 

 eggs, while another cave species, Nesticus pallidus, deposits from thirty to 

 forty.* It will thus be found, I tliink, that small and feebly organized 

 sjjecies tend to deposit a smaller numljer of eggs, altliough there are some 

 marked exceptions to this. 



The Peckhams give some interesting suggestions as to the relations 

 between fertility and exposure to peril. For example, the fact is pointed 



out that while Argiope cophinaria is sufficiently well protected. 



Fertility j-^gj. cocoons are exposed to serious loss through the assaults of 



,^ ichneumon flies, and, perhaps, also through exposure to the 



weather. Professor Wilder suggests that the immense fertility 

 of Nephila plumipes is counterbalanced by the destruction of its cocoons, 

 wliich are so placed, depending from leaves, that great numbers of them 

 are washed away and destroyed by rains. 



The little Attid spider Synagales picata lays three eggs. Yet, beyond 



' Araneffi Svecise, page 31. ^ The Peckhams. ^ Staveley. •* Packard. 



