ART. 1. NORTH AMERICAN SAWFLIES ROHWER. 19 



Upon hatching the larva does not eat the skin of the egg but 

 leaves it in the puncture. Besides shedding and changing its di- 

 mensions as described under " Larval Instars ", the larva characterizes 

 its advance, somewhat by a dijfference in the extent of its feeding. 

 The larvae during the first two stages, skeletonize small separate 

 splotches usually from the underside of the leaflet. Late in the 

 second stage or early in the third the larvae begin to cut holes 

 through the leaflets. By the fourth stage the holes are cut clear 

 through to the margin of the leaf and some of the edge is eaten, 

 including small veins. The fifth stage larvae feed on the entire leaf, 

 usually stopping only for the heavy midrib and bases of the larger 

 veins. 



When full grown the larva stops feeding and crawls about search- 

 ing a place suitable for cocooning, in the meantime evacuating by 

 the usual method, its alimentary tract. During this process it 

 changes in appearance from geenish white to a yellow or a leaden 

 white but neither sheds nor otherwise changes in character. The 

 cocoon is spun in the leaves, usually in a curled leaflet. 



In the foregoing table, as in the description of " Larval Instars ", 

 the male and female fifth stages are made separately and the sixth 

 stage is represented only in the female. This treatment indicates an 

 influence of sex upon the number of larval stages which is worthy of 

 especial mention. The male larvae have one less stage than the 

 female. In the fifth stage of the male (which is comparable with the 

 fifth stage of the female in size, proportions, and other characters) 

 the male larva feeds, empties his elimentary tract, and without shed- 

 ding spins his cocoon. The female larva, however, sheds to become 

 larger, feeds again, and without shedding in this sixth stage, spins 

 her cocoon. Thus the male larva has five instars while the female 

 has six. Another interesting feature which was discovered in the 

 study of this insect's development in the absence of a distinct pre- 

 pupal stage. In this respect not only is the spinning stage identical 

 in appearance with the feeding form but there is neither a shedding 

 of the skin nor a loss of hairs between feeding and cocoon spinning, 

 during the spinning nor after it until pupation occurs. This is a 

 peculiarity of note especially in view of the striking changes usually 

 exhibited in the sawflies previous to spinning. In the Nematinae, 

 a subfamily close to and much like the Cladiinae, this prepupal stage 

 is clearly defined. Of what significance this change from the usual 

 method of development of sawflies is, the authors hesitate as yet to 

 form an opinion. 



The following information was obtained from notes made on a 

 number of larvae of both the first and second generations during the 

 period between the molting of the penultimate stage and the emer- 

 gence of the adult. This period is divided into several portions; 



