138 Psyche [October 



galleries. It varies from 2 mm. to 4 mm. in diameter and is usually 

 by no means large enough to accommodate all of the inhabitants 

 of the burrow at one time. Radiating from this nuptial chamber 

 are from three to nine egg-galleries, each made by a different 

 female. These lie nearly entirely in the sapwood grooving this 

 deeply and scoring the inner bark only slightly. Where the egg- 

 galleries are numerous they start from the nuptial chamber in all 

 directions, often being nearly symmetrical in their arrangement 

 near their origin (Plate VIII, fig. 2), when the engravings are in 

 the larger limbs or tops. However, those galleries which start 

 transversely or diagonally to the grain of the wood, soon curve and 

 are continued in a general longitudinal direction. 



As has been stated, the egg-galleries vary in number from three 

 to nine and in the material studied there was an average of nearly 

 six (5.7) to the engraving. With such a great preponderance of 

 females it might be expected that they would show a decrease in 

 fecundity as compared with other bark beetles. Yet such is not 

 entirely true for in 58 egg-galleries studied, the average number of 

 egg-niches is 28, as compared with 19.05 in Ifs. longidens^ Sw., 

 19.89 in Pityogenes hopkinsi^ Sw., 20.84 in Polygraphvs rufipennia^ 

 Kirby and 30.65 in Eccoptogaster picea'^ Sw. But the most 

 extraordinary characteristic of the engravings of these little beetles 

 is the length of the egg- galleries. A study of a number of en- 

 gravings shows that these galleries made by the females vary in 

 length from 6 mm. to 250 mm. (10 inches), with an average of 89.6 

 mm. for sixty-two egg-galleries. When the small size (1.6 mm. 

 long) of the beetles is taken into consideration, it is seen that the 

 female whose egg-gallery is 10 inches long (Plate VIII, fig. 3) had 

 actually mined through the sapwood for a distance equal to 156 

 times her own length. The extraordinary length of these gal- 

 leries is also brought out by comparing their average length of 89.6 

 mm. with those of P. hopkinsv' (23.1 mm.), P. rufipenni^ (24.55 

 mm.), E. picece^ (27.36 mm.) and L. longiden^ (18.8 mm.). 



The egg-galleries of P. granvlahis differ from those of most 

 scolytids also in that they are not kept free of frass, but with the 



1 Blackman, 1919, Psyche, Vol. 26, p. 88 



2 Blackman, 1915, N. Y. S. Coll. Forestry, Tech. Pub. No. 2, p. 50. 



3 Blackman and Stage, 1918, N. Y. S. Coll. Forestry, Tech. Pub. No. 10, p. 45. 

 *0p. cit., p. 53. 



5 Loc. cit. 



