THE STATE ENTOMOLOGIST. 



73 



points where the winters are mild, they may even hybernate in the 

 larva state. 



This worm is a most voracious feeder, and a single one will some- 

 times strip a small vine of its leaves in a few nights. According to 

 Harris it does not even confine its attacks to the leaves, but. in its 

 progress from leaf to leaf, stops at every cluster of fruit, and either 

 from stupidity or disappointment, nips off the stalks of the half-grown 

 grapes and allows them to fall to the ground untasted. It is fortu- 

 nate for the grape-grower, therefore, that Nature has furnished the 

 ready means to prevent its ever becoming excessively numerous, for 

 I have never known it to swarm in very great numbers. The obvious 

 reason is, that it is so freely attacked by a small parasitic Ichneumon 

 fly— belonging to a genus (Microgaster) exceedingly numerous in 

 species— that three out of every four worms that we meet with will 

 generally be found to be thus victimized. The eggs of the parasite 

 are deposited within the body of the worm, white it is yet young, and 

 the young maggots hatching from them feed on the fatty parts of their 

 victim. After the last moult of a worm that has been thus attacked, 

 numerous little heads may be seen gradually pushing through dif'er- 

 ent parts of ils body; and as soon as they have worked themselves 

 so far out that they are held only by the last joint of the body, they 

 commence forming their small snow-white cocoons, [Fig. 48.] 

 [Fi g . 47.] which stand on ends and present 



,the appearance of Figure 47. In 

 about a week the fly (Fig. 48, «, 

 magnified ; £, natural size) pushes 

 ' open a little lid which it had pre- 

 viously cut with its jaws, and soars away to fulfil its mission. It is 

 one of those remarkable and not easily explained facts, which often 

 confront the student of Nature, that, while one of these Hog-cat er- 

 pillars in its normal and healthy condition may be starved to death 

 in two or three days, another, that is writhing with its body full of 

 parasites will live without food for as many weeks. Indeed, I have 

 known one to rest for three weeks without food in a semi-paralyzed 

 condition, and after the parasitic flies had all escaped from their 

 cocoons, it would rouse itself and make a desperate effort to regain 

 strength by nibbling at a leaf which was offered to it. But all worms 

 thus attacked succumb in the end, and I cannot conclude this ar- 

 ticle to better advantage than by reminding the Grape grower, that 

 he should let alone all such as are found to be covered with the white 

 cocoons above illustrated, and not, as has been often done, destroy 

 them under the false impression that the cocoons are the eggs of the 

 worm Numbers of these little white cocoons are sent to me every 

 year under the supposition that they are eggs, and no doubt many of 

 them get destroyed by the very persons who ought to cherish them. 



