1903.] A NEW SPIDER FROM CEYLON, 51 
and Green was resting upon the leaf in the normal position, that 
is to say back uppermost (figs. 1 & 2). 
Forbes, however, expressly states that P. decipiens, the species 
he discovered, lies back downwards on the web, holding itself 
in place by means of the spines with which the anterior upper 
surfaces of the legs are furnished, and he adds that the under- 
side of “its rather irregularly-shaped and prominent abdomen 
is almost all white, of a pure chalky white” (p. 587), and that 
“its pure white abdomen represents the central mass of the bird’s 
excreta, the black legs the dark portion of the slime.” Refer- 
ence, however, to his figure, which was apparently drawn partly 
from memory, the leaf "and web having “ gone astray” during 
the transport home, shows that the under side of the abdomen, so 
far from being almost all white, is furnished with a large black 
sub-oblong patch, which extends from its anterior border con- 
siderably past the middle. It is noticeable, too, that from the 
ventral aspect the abdomen is not irregularly shaped, but evenly 
oval in outline and devoid of tubercular excrescences. The dorsal 
surface, on the aes as represented in the figure given by 
Mr. Cambridge (BZ. 1884, pl. xv. fig. 1), might very well 
be described as almost “il white and rather irregularly shaped. 
The white colour largely predominates, and the tubercles project 
prominently from the expanded posterior portion. Mention is 
made of these discrepancies between the figure and description, 
to justify the suspicion that Dr. Forbes may have mistaken the 
dorsal for the ventral surface of the spiders he saw. Moreover, 
one cannot but wonder how the spider maintains a secure hold 
back downwards, especially when the powerful prehensorial legs of 
the first and second pairs are released, as released they must 
surely be, to seize an alighting butterfly. One would think that 
the flapping of the insect’s wing would pull the spider, now 
insecurely anchored, from its hold and bring both to the ground 
together. On the other hand, if the spiders of this kind always 
rest in the normal position seen and photographed in the case of 
P. rothschildi, the simulation of the bird’s-dung is equally perfect, 
and the spider, while seizing a butterfly with its fore legs, can 
maintain itself securely in place by grasping the web with the 
claws of the remaining pairs and by gluing its spinning-mamillee 
to the subjacent silken threads. 
These, then, are the points for further investigation which we 
would ask residents in the tropics to take note of :—Do the species 
of Phrynarachne assume indifferently the dorsal or the ventral 
attitude? Is it a peculiarity of one species to lie back uppermost, 
and of another belly uppermost? If they lie, as Forbes asserts, 
back downwards, how is a secure hold maintained when an insect 
has to be seized ? 
EXPLANATION OF PLATE X. 
Phrynarachne rothschildi, sp. n., p. 48. 
Figs. 1, 2. The ue resting on Jeaf. Fig. 3. Upper surface. 
Fig. 4. Under surface. Figs. 5, 6. Byes. 
4% 
