MOULTING HABITS OF SPIDERS. J 05 



skin recovered from the burrow it had succeeded in casting tlieni all off 



without any mutilation. The spring of 1887 was a backward one, and I 

 experienced great difficulty in procuring insects for food from 



Bftect of ^]jg immediate neighborhood. The annual supply of grasshoi* 

 , pers and locusts upon which I had relied came very late. Per- 



haps had the spider been strengthened by a few weeks generous 



feeding previous to its last moult it might still have been alive 



vn. ^\ 



With each moult spiders undergo a change in color and patterns more 

 or less decided. Some species have such neutral colors and are so uni- 

 formly marked that the differences are not decided ; but some 

 p. undergo such decided changes that diiferent species have been 



established for the same sjiider upon specimens taken after differ- 

 ent moulting periods. In some species the colors and markings of the 

 youngling, after the first moult or two, fairly represent the markings at 

 maturity ; in others the difference is so great between the two stages of life 

 that it is quite impossible to identify young individuals, or distinguish the 

 young of several species with accuracy. 



Among the young of Lycosa and Attus, according to Wagner, these mod- 

 ifications are effected with the female and male so equally and uniformly 

 during the first four or five moults, and with Trochosa during the first six 

 or seven moults, that one is scarcely able to distinguish the sex. With the 

 final moults these distinctions become more and more marked, though not 

 always to the same degree. The differences in relative length of legs and 

 in the shape of the palps also begin to appear ; for example, the male 

 Trochosa singoriensis at the seventh moult ec^uals in body size and rela- 

 tive length of the legs those of the female at the sixth moult. Tlie same 

 is true of Attus. 



Among Orbweavers generally, and in spiders of vaiious tribes observed, 

 the change in color (and in form also) is most decided in the males ; that 

 is, the young male carries the typical colors and general shape 

 ^ , of the adult female ; the younglings of Ijoth sexes after the 



initial moults resemble each other perfectly, and tend to resemble 

 the adult female. Thus the young male of Dictyna philoteichous bears a 

 close likeness in color and pattern to the adult female; but after final moult 

 the difference in color is quite marked, as well as in shape of palps and 

 contour of body. 



Professor Peckham^ finds a close resemblance between birds and spi- 

 ders in their moulting changes, and his sjiecial studies of the Attidae are 



' Occasional Papers, Nat. Hist. Soc, Wisconsin, Vol. I., 188!i, page 16, (ieorge W. and 

 Elizabeth G. Peckham. 



