372 Phylum Arthropoda 



then the selected larvae or pupae may be added. It is necessary to keep 

 the filter paper or sand wet, but not submerged, during the life of the 

 culture. Since it is probable that the actual food material of nearly all 

 wood- and fungus-inhabiting larvae consists of mycelia and other soft 

 parts of the mixed flora of fungi (and sometimes algae) that grows on the 

 wood or larger fungous body, it would seem logical to re-infect the 

 previously dried material with scrapings from the original, undried wood 

 or fungus, but this procedure usually seems unnecessary. 



With some exceptions, the precise species of wood or fungus does not 

 appear to be a specific requirement. Limonia cinctipes, L. macateei, and 

 L. rara have been carried through 4 to 12 successive generations in a 

 supply of dried and re-wetted Polyporus tsugae. A large supply of this 

 fungus was collected and dried in North Carolina and then brought to 

 Florida where it does not occur. In it a stock of L. cinctipes, obtained 

 in Florida from a Polyporus sp. on a sweet-gum (Liquidambar) ; also 

 a stock of L. macateei, obtained in Florida from Poria sp.; another stock 

 of L. macateei, obtained in North Carolina from Polyporus tsugae; and a 

 stock of L. rara, obtained in Florida from mycelium-riddled wood of a 

 Magnolia log, were all successfully maintained as long as the supply of 

 the re-wetted fungus was provided. For L. cinctipes, a new supply was 

 required about every two generations ; for the other species, about every 

 four generations. 



A "Polyporus agar," made by steeping shreds of fresh Polyporus for 

 a week or so in tap water and then boiling, straining, and adding suffi- 

 cient dry, plain agar to make the infusion set when re-boiled and cooled, 

 forms a medium in which L. macateei and L. rara will oviposit freely; 

 the eggs will hatch and the larvae feed and grow. The agar is poured 

 into the usual petri dishes and, when set, the cover is temporarily re- 

 placed by a lantern globe with screened top, set directly on the agar. 

 Mated females, introduced from the rearing jars containing fungus, not 

 only oviposit but infect the agar with spores so that mycelia soon pene- 

 trate the agar in all directions. It is the mycelia that furnish food for 

 the young larvae, and the movements and feeding of the latter may be 

 watched under a binocular microscope until the agar becomes opaque 

 from fungous and bacterial growth. Transfers of the larvae to fresh 

 plates inoculated with smears from decaying fungus may easily be made, 

 but if visibility of the larvae is not required they will thrive in the original 

 plates as long as the agar neither liquifies nor dries out. Accumulations 

 of moisture on the surface of the agar are likely to drown the larvae. 



