186 



INSECTS INJURIOUS TO THE PLUM. 



as they leave the fruit to enter tlie groiincL A minute 

 yellow Thrips, scarcely one- twentieth of an inch long, is 



Fig. 198. 



said to seek out and devot^r large quantities of the eggs of the 

 curculio. 



Fig. 199. Two species of parasites 



are known to attack the 

 larva of this pest. One, 

 known as the Sigalphus 

 curculio parasite, Sigalphus 

 curculionis Fitch, is a small ^ 

 black, four-winged fly, rep- 

 resented in Fig. 198, where a shows the male, and b the 

 female. With her sharp ovipositor the female punctures the 



skin of the curculio larva, 

 Fig. 200. ^ ^ -. i 



and deposits an egg under- 

 neath, which in due time 

 produces a larva, as shown 

 at a. Fig. 199. When the 

 curculio larva is destroyed 

 by the parasite, the latter 

 encloses itself in a small, 

 tough cocoon of yellowish 

 silk, b, and then gradually 

 assumes the pupa state, as shown at c ; all these figures are 

 magnified. The other species, known as the Porizon curculio 



