422 THE ZOOLOGIST. 
Nov. 26th. When they meet an ant they spring with great 
quickness to one side. On March 14th, 1902, when I was turn- 
ing out my F’. rufa observation nest, I found in a cleft in a bit of 
wood the nest and eggs of this spider. 
This year I put specimens into small plaster nests, with ants, 
beetles, and small Diptera, &c., all taken or bred out of my rufa 
observation nest. The ants never molested the spiders. On one 
or two occasions I saw the T'hyreosthenius feeding on one of the 
little flies (Phyllomyza formice and Sciara sp. ?), though I never 
actually saw the flies caught. I should say they certainly prey 
on small flies and other very small insects, &c., in the nests. 
Evansia merens, Cambr.—This species was described from a 
male taken by Mr. Evans at Glenfarg, Perthshire, in 1899. Its 
connection with ants was not then mentioned, but Mr. Evans 
tells me he took it with ants. In 1901 Mr. Randell Jackson 
took both sexes (the female, of course, being new to science) with 
Lasius niger in Glamorgan. In June, 1903, I took a specimen 
in a nest of Formica fusca at Hayton Moss, in Cumberland, and 
in June, 1905, five specimens in a nest of the same ant at Bar- 
mouth. Mr. Jackson also found it with the same ant in the 
Tyne Valley. He writes :—‘‘ The spiders are found either in the 
galleries or on the under side of the sheltering stone. They are 
amongst the ants, and not merely hiding under the edges of the 
stone as so many other spiders do. They are not enclosed in 
cocoons, but the ants do not molest them. Adults may occa- 
sionally be found throughout the year, but most of the males are 
mature in September and October. The species ascends about 
1000 ft. in Glamorganshire.” Mr. Bagnall has taken it with 
F, fusca at Winlaton, and I found it with the same ant in 
September this year at Nethy Bridge, Inverness-shire. 
Tetrilus arietinus, Thor.— This spider was described from 
ants’ nests in Sweden. In 1900 I took an adult and an imma- 
ture male in nests of Formica rufa’ and Lasius fuliginosus at 
Oxshott, its first record for Britain. In September, 1901, Randell 
Jackson took a female with brood under a stone, but not with 
ants, on Craig-yr-Eglwys. He mentions there were numerous 
colonies of L. niger about, but did not notice any connection with 
the ants. Father Wasmann gives F. rufa and L. fuliginosus as 
its hosts. 
