LETTER OF OCTOBER 10TH, 1859. 25 



One of the most interesting species amongst the cocoons 

 I sent to you will doubtless be Phyllocnistis vitigenella. The 

 larva mines the leaves of Vitis cordifolia in an exceedingly 

 long, winding, narrow tract, just sufficiently broad to accom- 

 modate its body. The tract is not transparent, and the 

 entire parenchyma of the leaf is not consumed, so that in 

 appearance it is not unlike the tracings left by snails. Just 

 before undergoing its transformation the larva enlarges its 

 mine sufficiently to enable it to throw the leaf into a small 

 fold and weave its cocoon. 



The larva is without feet or prolegs. The body tapers 

 posteriorly somewhat, with the sides of the segments slightly 

 projecting, but flattened, and the middle cylindrically ele- 

 vated. The head is thin, flat and circular, with the man- 

 dibles forming an appendage in front in the median line. 

 The head is umbre-brown. The body shining, translucent, 

 whitish on the sides and dark green in the middle. It is 

 somewhat viscid, adhering to whatever touches it after the 

 larva is taken from the mine. When this is done, it makes 

 little or no voluntary movement and does not retreat in its 

 mine when touched. The larva is apparently very delicate 

 and is easily killed, indeed, does not survive the gentlest 

 handling and examination. 



All the specimens I found in the larva state produced 

 perfect insects some time past, but, fortunately, the day before 

 I sent the box to you I found four or five mines, the Iarva3 

 in which were just preparing for pupation. I secured these 

 for you, and as soon as I was sure they had begun to weave 

 I packed them in the box. When they appear I think you 

 will find I have not mistaken the genus. 



In the leaf of the same plant ( V. cordifolia) I found, a few 

 weeks since, another Antispila larva, another much larger 

 one in a species of domestic grape (the Isabella), another in 

 a species of Cornus, and on the day I went out for your 

 benefit still another species in the leaf of the Hickory.* So 



* Carya, a genus of Juglandacece. H. T. S. 



