INSECTS INJURIOUS TO THE PINE. 209 
flattened on the side of attachment, and slightly so on the opposite side. 
Their average diameter is 1.4™™ (.05 inch), The general color is reddish 
brown, differing in intensity with the stage of‘development. The sur- 
face of each egg is marked with numerous delicate carinze, which meet 
at the center, somewhat resembling those of the cotton and boll worms 
figured in the article on cotton insects. We have not proof positive 
that these are the eggs of this leaf miner, but their size, appearance, 
and place of deposit seem to indicate that they are. 
“The work of the growing larve is well shown in the plate, and also 
the larva itself, highly magfified. From a study of the mines, the larva 
appears to burrow towards the end of the leaf first. Should it arrive 
at the end of the leaf (and it almost invariably does) before attaining 
full growth, it reverses its position and.mines towards the base. The 
hole of entrance and of future exit is apparently in all cases enlarged 
and the excrement pushed through, as there is but little frass to be dis- 
covered in the mine, while it can always be found in a greater or less 
quantity at the opening or on the leaves below. No instance bas been 
observed in which one larva has injured more than a single leaf of P. 
rigida; but a specimen of this insect was found in. Virginia upon the 
common scrub-pine (P. ‘nops), the leaves of which are shorter and more 
‘slender than those of the pitch-pine, and, from observations made upon 
it, it would seem that one leaf, if small, does not afford all of the food 
needed by a larva. 
‘¢ When found on the Ist of January this specimen was hibernating, the 
mouth of its burrow being covered with a thin silken curtain. Six days 
after, being transferred to a warm room, it was found that this curtain 
had been broken and the insect had left its mine. It was soon found on 
another leaf, and the same day formed a new burrow, where it contin- 
ued to eat until January 23, at which time it had completely excavated 
the leaf. After this date all operations appear to have been suspended, 
and there were no signs of life in the burrow until March 3, when a 
Proctotrupid parasite issued. 
‘Leaves of P. rigida are frequently observed to be completely mined 
out, and nearly full-grown larvee are occasionally found crawling about 
over the leaves and twigs; so it seems probable that with this species 
of pine also two leaves may sometimes be successively mined by the 
same larva. 
“The full-grown larva is nearly 5™" in length (.19 inch). Its color is 
light brown, with the head and prothoracie shield and the anal plate 
black. The body is clothed with a few delicate hairs. The form of the 
larva is Shown in the figure. Upon reaching full growth the larva spins 
a slight covering to the mouth of the mine and retreats a short distance 
above it (from 10™™ to 15"™). There, after spinning a few supporting 
lines of silk, it transforms to a long and slender chrysalis, light-brown 
at first but afterwards nearly black. When removed from the mine the 
pupa is very active, jerking the short end of the abdomen (which ex- 
14 RIL 
