THE HOP GRUB—ITS HABITS. 35 
heads,” Lam informed by growers, were quite common this spring. The 
heads had been opened and the larva detected, but the parentage was: 
almost universally attributed to a ‘“‘ green fly” mentioned, but not more 
nearly described in several agricultural papers. This fly, as nearly as } 
can make out from the description of growers, is a Syrphus, and prob- 
ably the parent of the larva found afterward destroying the hop aphis. 
At any rate, it is not the parent of this ‘‘tip worm,” as the insect has 
been called. Not all “muffle heads” are caused by this larva, how- 
ever, as will be hereafter pointed ont. 
When the insect attains a length of about half an inch or slightly 
less, it leaves the tip, drops to the ground, and, entering the stem at the 
surface of the vine, feeds upward, interrupting the growth of the vine and 
lessening its vitality; the larva now changes color, and becomes a dirty 
white with a strong, deep reddish tint, apparently proceeding from be- 
neath the surface of the skin, and with numerous black spots. As the 
vine grows, it becomes hollow and hardens, and the more rapidly as the 
free flow of sap is interrupted. The larva, now about an inch in length, 
and still slender, burrows downward to the base of the vine at its june- 
tion with the old stock, and, eating its way out, completes its growth 
as a subterranean worker ; it is in this state that it is best and most 
widely known as the hop “grub,” and the ravages caused by it are 
most noted. 
The journey from the stem to the ground is made in the beginning of 
June, and by the 21st of June, while I found many larvee in the ground 
about the roots, none were found in the stems, though traces of their 
work were everywhere abundant. 
The larva now is mainly a sap feeder. Iteats a small hole into the 
side of the stem just below the surface and just above the old root, and 
grows fat rapidly on the juices that should nourish the plant. As the 
sap seeks courses to enable it to reach the upper part of the vine un- 
molested, the grub enlarges its opening until he sometimes severs it en- 
tirely from the parent root, and the vine dies. In other cases it is left 
barely attached to the root, and continues a precarious existence, yield- 
ing few or no hops. Occasionally an exceptionally healthy vine will en- 
tirely recover from a serious attack of “grub.” By the middle or the 
20th of July the larve are full-grown and ready to enter the pupa state. 
They are now about 2 inches in length, fleshy, unwieldy, and very slow 
in their movements; they are of a dirty white color, speckled with fine, 
brownish, elevated tubercles, each furnished with a single stout hair ; 
the head is brownish and corneous, as is also the top of the first segment. 
About the 20th of July the pupa is formed in a rude cell close to the 
‘roots of the plant, upon which, during its larval existence, the insect fed. 
The pupa is an inch or slightly more in length, stout, cylindro-conic, and 
of a deep brown or blackish color. In this condition it passes the win- 
ter, though, as before remarked, a few specimens appear in the fall. 
Whether these latter hibernate or whether they perish, I have not been 
able to ascertain, though the latter seems the more likely. 
