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HABITS OF I^ARVAE 



As the popular name, fungus-gnat, indicates, the larvae feed up- 

 on fungi in the great majority of cases. The species of fungi they 

 attack and the situation in which the larvae are found differ very con- 

 siderably. Many species feed upon Agaricus and allied genera in open 

 situations ; some feed upon Polyporus and other fungi growing upon 

 living or dead trees ; while others feed upon minute fungoid growths 

 upon the under surfaces of fallen trees, rails, or boards upon the 

 ground, and a few appear to live entirely upon vegetable matter in an 

 advanced stage of decay. Nearly all the larvae spin webs in the gal- 

 leries they make in their food; in the case of species that live exter- 

 nally upon fungi the web is slimy, rather loose, and irregular. I have 

 paid particular attention to some species I have reared, and find that 

 the larvae of this last group do not pass over the threads but through 

 them, as in a tube, the body being enclosed except anteriorly. The 

 threads are slimy in nature, and the presence of the larvae may be de- 

 tected by the glistening surface of the fungus, which appears as if a 

 slug had crawled over it. The larvae, as far as I have observed, spin 

 a cocoon of a more or less compact nature to pupate in. In the case of 

 Leia the pupa is simply suspended by means of a number of loose 

 threads which keep it from the surface of the fungus or other matter 

 in which it is found, and very probably safeguard it to some extent, 

 as mites seem unable to cross the threads. 



HABITS OF IMAGINES 



The imagines are found in a variety of situations, but most com- 

 monly in damp and rather dark places, especially where there is fun- 

 goid growth. Damp basements, old outhouses, and hotbeds, usually 

 yield many species. In woods the greatest number may be obtained 

 by sweeping amongst undergrowth in the most shady spots, though 

 a number of species may be found on tree-trunks, where they run with 

 surprising speed. Several species occur upon flowers, but the major- 

 ity of them only in the late afternoon. ]\Tanv species will on occasion 

 feign death, but spring to life suddenly when touched. I have found 

 specimens still enclosed within their loose silken cocoon when collect- 

 ing under bark in spring. When touched the insects make a hurried 

 exit only to feign death after progressing a few inches, and by means 

 of alternate rushes and pauses they soon succeed in burying tliem- 

 selves imder anv loose detritus that is convenient. 



