112 University of California Publications in Zoology (Vou. 9 
glass-- E / a 
~bm. 
alla 
Fig. D. Transverse vertical sectional view of constant-temperature box 
for microscope. The regulator, which is at one end of the box and not 
opposite the microscope, is projected on the drawing. The air circulation is 
indicated by the arrows. a, place where cloth is attached; bm., longitudinal 
supporting beam for wire netting floor; glyc., glycerine-filled tube of regu- 
lator; mer., mereury-filled U-bend of regulator. xX &. 
