18 BULLETIN 1053, U. S. DEPARTMENT OF AGRICULTURE. 



decays and insect burrows (cf. Spaulding, 56; 57, p. 115), but little 

 is known as to how great an extent insects are responsible for carry- 

 ing the spores of these fungi and starting infections. Hubbard (£5, 

 p. 251) reports that several bark insects have been found within the 

 veil of Cryptoporus volvatus and suggests that such insects may 

 carry the spores from fruit bodies into direct contact with the inner 

 layers of bark of uninfected trees. One beetle (Epuraea monogama 

 Crotch) he found (p. 253) always coated with a thick layer of the 

 spores. Zeller (63, p. 124) has made similar observations in connec- 

 tion with the same fungus. The common occurrence of fungus gnats, 

 mites, springtails, and slugs upon hymenia has been noted by several 

 (Buller 8, pp. 19,20,23,96). 



The fruit bodies of Trametes serialis mentioned above appeared at 

 a time following a thaw when a considerable quantity of water seeped 

 into the fungus pit from the earth below, making a damp chamber of 

 the whole pit. The dampness caused an abundance of spores to be 

 cast. The beams bearing the sporophores were so situated that they 

 were about 1 centimeter above a piece of plank. It was so moist in 

 this space that water had collected on the plank under the sporophore 

 and this water was full of basidiospores. With the advent of moist 

 conditions within the pit also came sow bugs. They infested the 

 woody material and were particularly abundant on and around the 

 fruit bodies, even wallowing in the water full of basidiospores. A 

 number of these animals, with small spiders and springtails asso- 

 ciated with them, were collected and examined for spores and, of 

 course, were found to bear great quantities of them. All animals 

 collected on that particular beam had spores in varying quantities 

 on their legs, antennae, and setae, and many of them, particularly the 

 sow bugs, had a large number of spores upon their backs where they 

 had fallen directly from the sporophore. A photomicrograph (PL 

 VI, fig. 2) shows the immense number of spores on the appendages of 

 sow bugs taken from the water beneath the fruit bodies. Sow bugs 

 caught covered with spores as just described were transferred to 

 flasks of sterilized wood blocks and incubated. The blocks became 

 somewhat contaminated with Penicillium, as might be expected, 

 although not heavily, but a hymenomycetous growth was noted in the 

 flasks as well. After several months the blocks were removed and 

 found to be decayed, showing that the dissemination of wood- 

 destroying fungi by means of arthropodous animals is possible. 



The point to be made in connection with the relation of sow bugs 

 to the possible dissemination of basidiospores within buildings is 

 that the fruiting of these fungi and the presence of the sow bugs 

 are often tied up with moisture conditions. Certain fungi will fruit 

 in moist places, especially near the earth and in small inclosed places 



