20 



plight. Since they are unable to consume the rapidly ripening ambro- 

 sia, they must also wander forth, although wingless and weak in organi- 



Fig. 12. — Ambrosia of Xijleborv.s iwbescens found in maple — greatly enlarged (original). 



zation, or perish by suffocation. They therefore frequently assemble 

 in certain galleries to form bachelor colonies, where, by their combined 



numbers, they are able for a time to prolong 

 their existence.. They are found sometimes, 

 as Eichhoff relates, to the number of 50 or GO, 

 packed one behind the other in a single gallery. 

 The ambrosia of X pubescens has short 

 branching stems, terminated by single spher- 

 ical conidia. In fig. 12 is shown a form from 

 the gallery of a species belonging to this 

 group, found in maple. Another form of the 

 fungus is given in fig. 13. It was taken from 

 galleries of the typical species in orange wood. 

 A brown stain accompanies the fungus and 

 discolors it at the base of each cluster. 



A number of females which can not at pres- 

 ent be distinguished from X. pubescens Zimm. 

 have been described under the names X affinis 

 Eichh., X. perforans Woll., X. inermis Eichh., 

 X pini Eichh., and X propinquus Eichh. 

 The names X retusicollis and X planieoUis 

 were given by Zimmerman and LeConte to 

 two males which belong to the pubescens group. 

 The species of this group inhabit many kinds of trees. The same 



FlG. 13. — Ambrosia of Xyleborus 

 pubescens in orange — greatly en- 

 larged (orignal). 



