BURROWING HABITS OF SPIDERS. 31 
small abodes will be clustered about the old trapdoor. These vary greatly 
in size, but all are quite perfect in form. The smallest nest measured by 
Miss Thomson was barely three inches in depth, yet this was fitted with 
a diminutive circular door no larger than the nail of a lady’s little finger. 
The largest adult nest measured was twelve inches in depth. 
IX. 
Heretofore I have considered the nesting habits of spiders! and the 
influence of enemies upon their architecture (Vol. IL, Chapter XIII). 
Elsewhere I have tried to trace the relations between the nesting 
ios habits of the two great tribes, Citigrades and Tunnelweavers.? 
Opifee. A discovery lately made by Mr. W. A. Wagner, of Moscow, 
gives new interest to these statements and enables me to com- 
plete the chain of resemblances pointed out. The connecting link between 
the industry of the two tribes is found in Mr. Wagner’s Tarentula opi- 
phex,® a Russian spider of the family Lycosoide.4 The nesting habits 
of this spider are thus described by Wagner. It was observed in numbers 
in the Russian province of Orel, and dwells among the tufted vegetation 
of fallow lands, its principal habitation being fields of wheat and pota- 
toes. The species is agile in movement, active in habit, and compara- 
tively small in size, having a body length of less than one-half inch, ten 
millimetres. (Figs. 12, 13.) The burrow is not deep, that of the adult 
usually not exceeding two and a half inches; it is enlarged at the bottom, 
giving it a bottle shape (Fig. 15); is silk lined throughout, but the lining 
is extremely thin except toward the entrance; the walls are smooth and 
more carefully finished than usual with known Lycosids, as, for example, 
Trochosa singoriensis. 
But the most remarkable and distinct feature is the covering of the 
burrow, which is constructed after the well known type of the Trapdoor 
spiders, Figs. 14, 17, 18. This door consists of a single layer 
of silk covered externally with a coating of soil, whose pellets 
are bound together by a mesh of threads and spread unequally 
upon the surface, being much thicker in front than behind. It 
has the usual shape of the Trapdoor spider’s door, something more than 
semicircular, or a circular plate cut squarely across the end by which it 
is hinged to the burrow. (See Figs. 17, 18.) Instead of being beveled 
along the edge like the door of our Cteniza californica, and thus fitting 
into the burrow like a cork into a bottle, it rests when closed upon the 
surface edge of the burrow like a basket lid upon a basket. The front, 
or entrance end, projects beyond the burrow (Figs. 15, 16), making a sort 
Trapdoor 
making 
Lycosid. 
1 Vol. I., Chapter X VIII. 
* Proceed. Acad. Nat. Sci., 1887, Philadelphia, page 377, sq. 
5 Opifex ? 
_ * Bulletin Soe. Imper. des Naturalistes de Moscow, No. 4, 1890, 
