2)66 ARACHNIDA — ARANEAE chap. 



constructs a cocoon containing, on an average, 1150 eggs. As 

 many as 2200 have been counted in exceptional cases. Even 

 this number is exceeded in the case of some of the great 

 Aviculariidae. Theraphosa lehlondi deposits as many as 3000 

 eggs. The large European Epeirids, E. qiiachata and E. diadcmata, 

 lay about 600 eggs, those of Lycosa narhonensis reaching about 

 the same number. Those American spiders which have been 

 described as stringing up a series of cocoons in their webs usually 

 attain about the same aggregate, the eggs being less numerous 

 in each cocoon. 



These are examples of fairly large and fertile spiders. In the 

 case of other species the number of eggs laid is exceedingly small. 

 Ero furcata makes a single cocoon containing six eggs. Synagehs 

 picata, an ant-like Attid, lays only three. Oonops jjulcher con- 

 structs several cocoons, but each contains only two eggs. The 

 eggs of Cave-spiders, and such as live in dark and damp places, 

 are generally few in number. Anthrobia mammouthia, for 

 example, an inhabitant of the great American caves, deposits only 

 from two to five egg-s. 



Our knowledge of the special perils which beset particular 

 species is so incomplete that we are often at a loss for the 

 reason of this great inequality in fertility. For instance, how 

 does Synageles picata maintain its numerical strength by laying 

 only three eggs, when, as M'Cook points out, its resemblance to 

 the ant, though advantageous to the adult spider, affords no pro- 

 tection to the egg ? Our knowledge must be greatly extended 

 before we are able to account for particular cases. Many 

 influences hostile to spiders as a group are, however, well known, 

 and we may here enumerate them. 



Natural Enemies. — The precautions taken by the mother in 

 constructing the cocoon render the inclemency of the weather 

 very much less destructive to the eggs than to the newly-hatched 

 young. Nevertheless, among spiders inhabiting swampy regions 

 great havoc is wrought by the occasional wholesale swamping of 

 the cocoons by floods. Professor Wilder considers the great 

 fertility of Nephila 'plumi'pes necessary to counterbalance the 

 immense destruction worked by the heavy rains upon their 

 cocoons, which are washed in great numbers from the trees, to 

 the leaves of which they are attached. But such exposed situa- 

 tions are avoided by many species, and their eggs, enclosed in 



