444 FUNGUS-INSECT INTERRELATIONSHIPS 



FUNGI OCCURRING OX OR WITHIN INSECTS 



The entomogenous fungi, or fungi that naturally occur on or 

 within the bodies of insects, vary greatly in food habits. Some 

 utilize only living insects, whereas others subsist entirely as scav- 

 engers. Some exhibit a high degree of specialization; others are 

 quite generalized. Furthermore, with the exception of the La- 

 boulbeniales and nearly all the Entomophthorales and species of 

 Cordvceps, the entomogenous habit is not a characteristic pos- 

 sessed by any large group of closely related species. All seem 

 markedly influenced in their food habits both by biotic and en- 

 vironmental factors. 



.Much of our knowledge of these fungi comes from the investi- 

 gations of Thaxter (1888, 1896, 19o{ 1924, 1926) and Petch 

 0914, 1921, 1924, 1925, 1926, 1931, 1932, 1935, 1939). Thaxter 

 devoted his attention to the Entomophthorales and Laboulbeniales; 

 Petch, to various others, principally to Ascomycetes belonging to 

 Cordvceps, Hypocrella, Sphaerostilbe, Myriangium, Podonectria, 

 and Xectria, and to members of the Fungi Imperfecti belonging 

 to Aspergillus, Penicillium, Spicaria (Isaria), Aschersonia, Alicro- 

 cera, Yerticillium, Acremonium, Cephalosporium, Rhinotrichum, 

 Cladobotryum, and Beauveria. The student of entomogenous 

 fungi should also acquaint himself with the check lists by Seymour 

 (1929, pp. 698-718) and Charles ( 1941) to gain some appreciation 

 of the large number of species of fungi and insects involved. In 

 the following account mention will be made only of a few of the 

 better-known ones. 



In 1921 Keilin (1921) described as Coelomy ces stegomyiae an 

 organism parasitizing the larvae of the mosquito, Stegoviyia scu- 

 tellaris. Later Couch (1945) found additional species of Coelo- 

 myces in larvae of other mosquitoes, Culex and Anopheles, in 

 Georgia, and determined that the parasites belong among the 

 Blastocladiales. 



Among the better-known species of Entomophthora may be 

 mentioned E. vmscae on houseflies, E. grylii on crickets, and E. 

 sphaerosperma on the caterpillars of cabbage butterflies. Ento- 

 vwphthora sphaerosperma was reported by Sawyer (1929) as para- 

 sitizing Rhopobota vacciniaua, which attacks cranberry vines. 

 Speare (1912) described E. psendococci as parasitic on mealy bugs, 



