338 AMERICAN SPIDERS AND THEIR SPINNINGWORK. 



to it in this connection. Here, perhaps, we have a view of the greatest 

 mfluence exercised by color and, as one may say, the absence of color, upon 

 the life of araneads. 



When we come to consider the more highly colored species, particularly 

 in their relation to their habits, tlie question of utility is complicated by 

 many apparently contradictory facts. Such large and well marked species 

 as those of the genus Argiope, Acrosoma, Gasteracantha, and such brilliant 

 species as the Orchard spider, are found well nigh invariably hanging at 

 the centre of their webs in full view of all enemies and assailants. One 

 who is pursued by the theory of utility can scarcely fail to ask whether 

 these species are protected by their color from any enemies, and, if so, in 

 what manner are they protected? It is certainly natural to su}>i)0se that 

 they are more exposed thereby to raiding birds, digger and mud dauber 

 wasps. 



Another question may be mooted, have these species, thus highly col- 

 ored, and thereby exposed to enemies, any industrial protection which 

 may be considered a compensation ? I refer to a few exam- 

 Industrial p2gg- bearing upon this inquiry. Argiope cophinaria and Ar- 

 Compen- ^ . ^ / , /+• • t ,-, ^ ■ v 



.. gyraspis sometnnes have protective wings of retitelanan lines 



sation. bj i . , ^ . ^ . 



thrown out on each side of their nets, which guard the dorsal 



parts of their bodies, and a thick shield like sheeting, which protects the 

 under side. (See Volume I., Figs. 96 and S9.) These sjnders are highly 

 colored and conspicuous by size. They dwell in shrubs, bushes, grasses, 

 low trees, and commonly are stationed in the centre of their round webs, 

 having no domicile or tent to which they retire. No doubt, the pro- 

 tective wings are serviceable in warding off attacks of raiding wasps, as 

 well as helping to secure insect food for the occui>ant. But I find that in 

 a large number of cases these fenders are omitted. The tendency to omit 

 them, if I am not mistaken, strongly increases as the spiders mature in 

 age. Perhaps in this case the size of the animal may be considered as 

 sufficient protection. At all events, I think that the protective wings are 

 rather characteristic of the immature state. 



The Insular and Shamrock spiders, which are among the most In'ightlj' 

 colored of our fauna, do not hang habitually in the centre of their webs 

 during the day, but live in leafy tents, and their habitat is among bushes, 

 shrubs, and trees. The Insular spider inclines to groves much more strongly 

 than Trifolium. Epeira thaddeus has the same Iiabit. Indeed, it may be 

 asserted generally that many of our most highly colored Epei'roids belong 

 to tentmaking sjiecies, a fact which is true not only of the American, but 

 of the European, spider fauna. The facts here seem to point to a special 

 development of industrial protection as a compensation for the exposure of 

 bright colors. 



On the other hand, Epeira strix, which is not a bright colored spider 

 by any means, is one of the most secretive Orbweavers in its habits, dwelling 



