RIDDLE. — ON THE CYTOLOGY OF THE ENTOMOPHTHORACEAE. 189 



four, six, eight, and perhaps more, since Cavara was unable to follow 

 the process in its further development. 



Vuillemin (: 00) states that the early development of the azygospores 

 of Entomopldhnra gkospora is the same as in the acrogenous azygo- 

 spores described for E. Delpiniana. There is an ampulla into which 

 passes a single nucleus, which after the formation of a cross-wall, 

 divides to four, six, eight, and then to sixteen. It appears, however, 

 that this number is by no means constant, as Vuillemin records finding 

 twelve, fourteen, fifteen, seventeen, or eighteen, which he supposes to 

 be due to the failure of some of the nuclei to divide, or to a greater 

 number of divisions than usual. After the nuclei have reached this 

 number, there occurs successive fusion in pairs till the number is 

 reduced to two ; the azygospore rests in this condition for some time, 

 but these two also ultimately fuse so that the mature azygospore is 

 once more uni-nucleate. 



Vuillemin gives no figures for any of these numerous nuclear-divi- 

 sions and nuclear-fusions. His evidence seems to be based upon the 

 different numbers of nuclei in different cases and in their smaller size 

 when the number is greater. The number of the nuclei, however, 

 according to the results to be described presently, is closely dependent 

 upon the number in the hyphal body from which the azygospore is 

 formed. And the difference in size, apart from individual variations, 

 within restricted limits, which seem to be quite common (cf nuclei in 

 Figure 26), might easily be explained by the maintenance of the equi- 

 librium of nucleo-cj^oplasmic relations, the importance of which has 

 been shown by the recent work of Gerassimow (:01, -. 02, : 04), Hert- 

 wig (: 03), and others. As Vuillemin seems to cpnsider the conditions 

 described to be typical for the family, it will be well to compare the 

 account given above with results obtained from a study of the azygo- 

 spores of Empum Grylli 



After the hyphae of the fungus have broken up into h}T3hal bodies, 

 the formation of azygospores takes place. At some point on the hyj)hal 

 body, not necessarily at one end, a small protuberance appears, into 

 which there is a flow of protoplasm from the hyphal body ; the proto- 

 plasm stains more densely in this region and shows pressure. On 

 account of this pressure the protuberance continues to expand into 

 a rounded ampulla, the wall of which is at first only slightly thicker 

 than that of the hyphal body (Figure 26). Into this ampulla gradu- 

 ally passes all of the cytoplasmic contents of the hyphal body, to- 

 gether with all the nuclei, which the hj^^hal body originally contained. 

 Figure 26 shows a stage where this process is under way ; and Figure 

 27, a stage where it is completed. It will be seen here that the young 



