JOSEPH KRAFKA, JR. 



417 



Facet 

 number 



60 



50 



40 



30 



20 



10 



15° 20° 25° 30° 



Tempere^tupe 



Fig. 4. Temperature effect on the mean facet number in the Ultra-bar stock. 

 The upper curve is that of the males, the lower that of the females. 



Temperature Effect on Full-Eyed Wild Stock. 



In Table VII are given the counts of the full-eyed wild stocks reared 

 at 15 and 27°.^ They were made on material that was first boiled in 

 caustic potash, cleared, and mounted in balsam. The slides were held 

 in a mechanical stage while the facets were counted under a Zeiss 

 No. 8 objective and a No. 12 ocular. The ocular field was broken 

 up into rectangles by spider web cross hairs. One rectangle was 

 counted at a time. 



^ The counts of the full-eyed wild stocks reared at 27° are available through 

 the kindness of Dr. Zeleny. 



