10 



PSYCHE. 



[January — February i8S8. 



these parasites. They are so well known 

 as represented by the common house- 

 fly fungus, Euipusa muscae^ that I may 

 pass them rapidly by. The insect para- 

 sites of this group are variously classi- 

 fied : reduced by Winter to a single 

 genus (iSSi) ; distributed by Brefeld 

 (18S4) among three genera; and 

 divided by Eidam (1886) into four. 



Concerning their methods and appa- 

 ratus of attack on the insect body, I 

 need only note their similarity to those 

 of the Botrytis forms of the preceding 

 group — internal and external conidia, 

 thelatter germinating externally or in the 

 tracheae — the penetrating hyphae and 

 subsequent mycelium ; — the differences 

 are insignificant to the entomologist. 

 The conidia have, however, this impor- 

 tant practical peculiarity ; that they very 

 soon lose their power of germination, the 

 species being preserved from year to 

 year by lasting-spores — (large, thick- 

 walled, spherical cells forming within 

 the insect body, dark in some cases, 

 discoloring the blood) ; or else by the 

 hibernation of diseased individuals, in 

 whose bodies the fungus parasite is 

 preserved until the following year. In 

 grasshoppers, noctuid caterpillars, 

 cicadas, and the like, these lasting 

 spores almost completely fill the body 

 after death, the mycelium which devel- 

 oped them shriveling away. Destruc- 

 tive epidemics due to these fungi have 

 been noticed among grasshoppers — 

 especially Oedipoda and Pezotettix ; 

 among various noctuid larvae — espe- 

 cially Agrotis segetuni in Europe and 

 some American cut-worms ; among the 

 two European cabbage worms {Pier is 

 rapae and P. brassicae) ; among 



various diptera — the common house-fly, 

 blow-flies, syrphidae., Culex^ and even 

 Chironofnuslaxwsie ; and, finally, among 

 coccidae and aphides — Aphis corni and 

 Aphis rumicis — these last occurrences 

 suggesting to the agricultural entomo- 

 logists of France the use of Ento- 

 tnophthora for the destruction of the 

 phylloxera. 



These Entomophthora forms have 

 proved, thus far, much more difficult 

 of cultivation artificially than the other 

 fungus parasites, the only successful 

 attempt within my knowledge being 

 that made by Brefeld in 1884. In his 

 Entomophthorae (p. 72) he tells us that 

 after many unsuccessful trials he suc- 

 ceeded at last in cultivating them in 

 sterilized veal soup, the mode of 

 growth and of conidia formation being 

 identical with that in the body of the 

 living fly. 



In his J3otanische ttntersuchungen 

 for 1 88 1 he describes (p. 98) an infec- 

 tion experiment with the conidia of 

 Entomophthora radicans applied to 

 one hundred and twenty cabbage cat- 

 erpillars, with the consequence that 

 eighty-one speedily died of the fungous 

 disease resulting. 



In this country, three species only 

 have been described ; one by Peck 

 from the Cicada (Rept. Botanist, N. 

 Y. state mus. nat. hist., 31, p. 19), 

 first reported, however, by Leidy, in 

 185 1 (Proc. Acad. nat. sci. Philad., v. 

 10, p. 235) ; one by Bessey in Pezotet- 

 tix (Amer. nat., v. 17, p. 1280) ; and 

 one by Arthur from Phytonotfius punc- 

 tatus (N. Y. Agr. exper. station rept. 

 1885, p. 258). The only experimental 

 work attempted here grew out of the 



