348 REPORT OF STATE BOARD OF HORTICULTURE. 



third the width." Its shell is fairly tough and resistant, not sculptured and 

 sufficiently plastic, when laid, to receive impressions from the woody fibers 

 . between which it is forced. Oviposition has been observed from June to 

 September in a single locality (Lawrence, Kansas), but June is the month in 

 which most of the eggs are laid.* Pitch and others observed the beetles in 

 the trees, near Albany, New York, as early as April. 



The period of the egg from the time it is laid until it hatches, rests upon 

 the statement of Mr. E. W. Junkins that a young borer larva was observed 

 .July 7 from eggsf that were deposited June 15, which would give a period of 

 twenty-two days. 



The larvae soon after hatching tunnel under the bark and feed upon the 

 sap-wood, gradually working their way upward and afterward downward, 

 usually, particularly young trees, remaining within a short distance of, or 

 below the surface of, the ground. By the beginning of the second year the 

 larvae, according to recent observations conducted by the writer, attain an 

 average growth of about five-eighths of an inch. The larval growth will 

 naturally varj' according to temperature, moisture, and quantity of food 

 available for consumption, and other conditions. With the approach of cold 

 weather the lai'vse cease feeding, but with the beginning of warm spring 

 weather — in the District of Columbia as early as the latter days of March — 

 they again commence, forcing their excrement and castings consisting of 

 gnawed particles of wood out through holes which they make in their bur- 

 rows. By the end of the second year the larvse have increased considerably 

 in size and have now penetrated deeper into the solid heart-wood, their 

 burrows being closely packed behind them with castings. The third yeai- 

 the larvae gnaw outwards to the bark, form a pupal cell with the assistance 

 of their castings and, wtih their heads pointing toward the bark, transform 

 to pupse. With the approach of May and .June they cut their way out by 

 means of their powerful mandibles and issue through a round hole as mature 

 beetles. The period of the pupil stage does not appear to have come under 

 observation hitherto. A larva was observed by the writer at the Depart- 

 ment of Agriculture that pupated May 11, and appeared as adult May 30, 

 which gives nineteen days for this period; weather seasonable. 



NATURAL ENEMIES. 



Concealed as this insect is during its three years of existence in its pre- 

 paratory stages it is nevertheless a prey to natural enemies which seek and 

 devour it in its haunts under the bark. Of this number are woodpeckers 

 and hymenopterous parasites. Of the latter only a single species is known 

 to the writer, Cenocoelius populator Say. + 



METHODS OF CONTROL. 



After borers have once entered a tree there is no better remedy known 

 than to cut them out with a knife or other sharp instrument. In the treat- 



*Above quotations from account by Riley in New York Weekly Tribune, February 

 •20, 1878; Kansas Horticultural Report for 1879, pages 196-201. 

 fNew England Homestead, January H, 1885. 

 X Mentioned in Insect Life, Vol. Ill, p. 59, as Promachus saperdce Riley MS. 



