338 AMERICAN SPIDERS AND THEIR SPINNINGWORK. 



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

 influence 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, the question of utility is complicated by 

 many apparently contradictory facts. Such large and well marked sj^ecies 

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

 sijccies 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 suppose 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- 

 ples bearing upon tins inquiry. Argiope cophinaria and Ar- 

 Compen- ^ . ^ ,.^ , / ,■ ■ f ,-, , • ,• 



,• gyraspis sometnnes have j^rotective wnigs or retitelanau hues 



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 89.) These spiders 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 occuj)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 sjiiders 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 brightly 

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

 during the day, but live in leafy tents, and tlioir bahitat is among bushes, 

 s]irul)s, and trees. The Insular spider inclines to groves mucli more stronglj^ 

 than Trifolium. Epeira thaddeus has the same habit. Indeed, it ma_y be 

 asserted generally that many of our most highly colored Eijeiroids belong 

 to tentmaking species, 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 jDrotection as a compensation for the exposure of 

 bright colors. 



On the other hand, Epeira strix, which is not a bright colored si)iiler 

 by any nreans, is one of tlie most secretive Orbweavers in its habits, dwelling 



