Feb. is, 1921 Leconte's Sawfly, an Enemy of Young Pines 



75i 



From the cocoons of a single colony there are two periods of adult 

 emergence. The first period is termed "brood A," and the second 

 "brood B." When the colony period begins in late spring or early sum- 

 mer, brood A emerges in the late summer and early fall of the same year 

 and brood B emerges in the late summer and early fall of the following 

 year, making the length of the colony period 14 months. When the 

 colony period begins in the late summer, brood A emerges in the spring 

 and early summer of the following year and brood B emerges in the late 

 summer and early fall of the same year as brood A, making the length 

 of the colony period 12 months. 



Thus (see year II in fig. 1) we may have adults of brood B of the first 

 colony period, brood B of the second colony period, and brood A of the 

 third colony period existing in the late summer of the same year. In 



PlG. i.— Chart showing life and seasonal history of Neodiprion lecontei through the active period of three 

 years (November to March omitted, the insect being in the cocoon during this period). 



the spring, however, it is possible only to have brood A, but these may be 

 from different colony periods (see year III in fig. 1). 



The eggs are laid in a row of slits along one of the serrated edges of the 

 leaf (PI. 92, B) . These slits, the work of the female'ssaw, are about 1 .5 mm. 

 long and 0.8 to 0.9 mm. deep and have an interval between them about 

 equal to their length. They are somewhat shoe-shaped, the opening or 

 slit not entirely covering the pocket, and deepen slightly toward the 

 apex, or toe. These egg punctures are rather conspicuous, appearing 

 yellowish against the green of the undisturbed leaf tissue and becoming 

 brownish with age. Usually the leaves containing eggs die and become 

 noticeable some time after the hatching of the larvae. 



In cage experiments the number of eggs laid by single females varied 

 from 25 to 178, with an average of 82. In six virgin females dissected 

 the number of eggs varied from 58 to 218, with an average of 139, so it is 



