Feb. 15.1921 Leconte's Sawfly, an Enemy of Young Pines j/tf 



spiracular black spot on B, C 1 , C 2 , and the dorsad extremity of post- 

 spiracular area; a black spot on preepipleurite ; and sometimes a small 

 blackish spot on postepipleurite. The first and ninth abdominal seg- 

 ments are similar but have the preepipleural spot smaller and the post- 

 epipleural spot almost always absent. The tenth abdominal, or anal, 

 segment is white but with the epiproct black. 



LARVAL INSTARS 



The larval life of sawflies of the group to which this species belongs is 

 divided into two distinct periods by a change of objective. The form 

 and color of the larvae differ considerably in these two periods. In the 

 first period the larvae are active and, as they devote most of their energy 

 to feeding, change rapidly in size. There are usually six molts. In the 

 second period the larva is more contracted, less active, and devotes its 

 energies to seeking a place for and constructing the cocoon. No feeding 

 is done in this second period and there is no molting. This second 

 period is generally termed the prepupal period, but other American 

 writers have referred to it as the ultimate stage. 



These periods, stages, or instars are measured by the hatching of the 

 larvae from the egg and by the subsequent sheddings 01 moltings. The 

 larva molts after slightly varying passages of time, the extent of which 

 will be discussed later; and the molting, as a rule, is accomplished by the 

 longitudinal splitting of the prothoracic and mesothoracic skin mid- 

 dorsally, the breaking of the head capsule along the epicranial suture, 

 and the separating of the frons from the epicranium and the adfrontal 

 triangles. Through the opening thus formed the larva in its new skin 

 endeavors to extract itself from the old, and if successful begins feeding 

 anew, leaving the exuvia attached by the anal end to the needle. 



The following descriptions of stages and approximate length of each 

 are the summary of notes from numerous rearings of larvae in quantities, 

 since it has been found that isolation of larvae not only tends to retard 

 development but often causes death. This method makes impracticable 

 an absolutely accurate account of the time spent by particular larvae in 

 each stage. The first appearance of shed skins and of what seemed to 

 be a new stage was, however, recorded and was utilized for description 

 and as an index for these approximations. 



The larvae hatch from the eggs with slightly varying periods of incuba- 

 tion and develop at such different rates that following the first molt 

 there are always two and more often three or more stages present at one 

 time. From about the fifth stage a difference in size of the larva, depend- 

 ent upon sex, becomes noticeable, to confuse further an endeavor to de- 

 termine stages accurately. 



All the stages are similar to the sixth stage, except as noted in the fol- 

 lowing desciiptions. A detailed description of the sixth instar has 

 already been given under the heading "Larva." 



