198 



ROLAND THAXTER ON THE 



Fig. 



300. 



A zygospore wliich seems to liave resulted from a double conjugation. 



A gioup of sporophoi-es emerging from the host's body previous to the formation of zygospores. One of 

 their number has grown beyond the rest and subsequently forms part of a network which holds the 

 mass of external zygospores. 

 Two instances of external conjugation. 

 Conjugation taking place within the host. 

 Figs. 301-302. Further examples of external conjugation. 



Figs. 303-304. Resting spores formed internally, the process of conjugation not visible. 

 Fig. 305. Mature resting spore. 



Kmpusa (Entomophthora) sepulchralis n. s., figs. 306-326. 

 A cystidium somewhat immature. 



Tlie terminal portion of a cystidium at a more advanced stage. 

 A digitate conidiopliore arising directly from a spherical hyphal body. 

 A hyphal body beginning to germinate. 

 Primary conidia. 



Secondary conidia of the second type. 

 Primary conidium in which tl)e mother-cell wall has separated fron> the spore, remaining attached only at 



its point of dehiscence from the basidium. 

 Primary conidium in wliich the separation from the mother-cell has become complete. 

 Conjugation of two liyphae and first budding of the zygospore from one of the gametes. 

 Several stages in the formation of a zygospore. In fig. 325 the whole contents of the conjugating cells 



have passed into the zygospore. 

 Mature zygospore. (The circles of dots are due to careless engraving). 



Fig. 



326. 



♦Fig. 

 *Fig. 



Figs. 



Fig. 



Fig. 



Fig. 



Fig. 



327. 

 328. 

 329-342. 

 343. 

 344. 

 345. 

 346. 



*Fig. 347. 



*Fig. 348. 



Figs. 349-360. 



Fig. 361. 



Fig. 362. 



Figs. 363-365. 



Figs. 366-3G7. 



Figs. 368-3G9. 

 *Fig. 370. 



*Fig. 371. 



*Figs. 372-373. 



*Fig. 

 Fig. 

 Fig. 

 Fig. 

 Fig. 



374. 

 375. 

 376. 



377. 

 378. 



PLATE 20. 



Empusa (Entomophthora) variabilis n. s., figs. 326-345. 

 Compound conidiophore. 

 Rhizoids. 

 Primary conidia. 



Primary conidia among the first discharged. 

 Formation of a secondary conidium of the first type. 

 Formation of a secondary conidium of the second type. 

 Secondary conidium of second type. 



Empusa (Entomophthora) rhizospora n. s., figs. 347-37a 

 Conidiophore arising from spherical hyphal body. 

 Cystidium. 

 Primary conidia. 



Production of secondary conietinm of the first type. 

 Production of secondary conidium of the second type. 

 Secondary conidia of the second type. 



Production of " pseudoconidia" from hyphal bodies resulting from the general cfegeneration of the co- 



uidiophores. 

 Two of the psendocoDidia fully developed. 



Formation of a zygosjwre l>y the conjugation of the free ends of two hyphae. 

 Spiroijvra-Ukc conjugation resulting in the production of a spore from both gametes. 

 Two similar points of conjugation in which the liiizoid-like enveloping proce'sses are' clevelopiDc from the 



base of the spore. 



Group of mature zygospores showing indurated hyphae and rbizoid-like processes. 



A single zygospore. 



A zygospore freed from the episirore. 



A " Caddis fly" showing the growth of conidicrphores. 



Gross appearance of the zygospores produced externally over the host. 



*Fig. 

 Fig. 



PLATE 21. 



Empusa (Entomophthora) gracilis n. s., figs. 379-391, 



379. Conidiophore. 



380. Production of secondary conidium of the first type. 



