33 



adults were observed, ard none of the larvae I had under my observation matured ; so the 

 matter necessarily came to a rest. 



During the summer of 1883 the worms appeared in much greater numbers and dis- 

 tributed over many more trees. At the same time and upon the same trees with these 

 worms I observed adult Saw-flies that I could have little doubt were the mature worms, 

 although I did not succeed in finding the eggs and obtaining the larvge from them, nor 

 have I reared them as yet from the immature stage. Their presence in large numbers at 

 the time when the newly hatched larvae were appearing plentifully day after day, and the 

 fact that the adult must be an insect of this particular kind, left little doubt as to their 

 connection. During the present season I have observed these adults as early as April 

 15th, and the larvae but little later, while the eggs from which the larva? hatch were found 

 deposited in the petiole of the leaf. 



The adults are the Selandria barda of Say, the food plant of which, so far as I can 

 find, has never been recorded. 



No account of the larva or of its work is given in any of the works that I have been 

 able to consult, and as it seems to me of too much importance to remain unnoticed, I ven- 

 ture to give what I kriow of its history with the practical results of my study, notwith- 

 standing the doubts that rest over some parts of its life history. The pressure of other 

 duties at the time these worms were at work prevented me from giving them the time 

 they certainly deserved. 



Life History. 



The eggs are deposited in rows along the sides of the petiole just beneath the outer 

 bark, and so neatly that it is almost impossibe to detect any break in the epidermis. 

 Usually there are from six to ten on a leaf, Ihey evidently increase much in size before 

 hatching, pushing the bark up in a blister-like elevation, and if cub out of their covering 

 are found to be very soft, the outer membrane exceedingly delicate and easily ruptured. 



The larvae are evidently hatched within two or three days after the eggs are deposited, 

 and are at first slender, whitish worms with black heads and thoracic legs. They crawl 

 at once to the leaflets and appear to select the more tender ones for the commencement 

 of their work. They grow quite rapidly and reach the first moult on the third or fourth 

 day. Before moulting they are more whitish in colour, and the head particularly loses its 

 ordinary colour. After the moult the head is jet black and glistens like a glass bead ; the 

 six thoracic legs have also the same jet black colour ; otherwise the larva is clear green 

 with a slightly darker dorsal line. There are seven pairs of pro-legs or false legs along 



5.- S'-landria barda (Say). Leaf of ash showing position of eggs in petiole and work of larra. 

 3 (EN.) 



