AGRICULTURAL EXPERIMENT STATION. 141 



was awarded a premium of fifty dollars and a gold medal b}' the 

 Massachusetts Agricultual Societ}-. This insect has spread over 

 the greater portion of the United States and Canada and feeds 

 upon the foliage of the pear, quince, plum and cherry doing more 

 or less injury. Though called the pear slug it seems to prefer the 

 foliage of the cherry. 



FIG. 27, FIG. 28. 



DESCRIPTION. 



Perfect insect— A four-winged fly of a glossy black color. The 

 wings are transparent with brownish veins and the fore wings crossed 

 by dusky markings ; legs dull yellow with black thighs, excepting 

 the hind pair which is yellow in the middle and black at the extremi- 

 ties. The female is about one-fifth inch long and the male smaller. 

 The perfect insect is shown in Fig. 27, enlarged. 



The egys are small and deposited singly within semi-circular in- 

 cisions made in the skin of the leaf upon the upper or under side. 



The larva or slug when grown is about half an inch long, slimy, 

 blackish or olive brown ; head end smaller ; head small, reddish, 

 and nearly concealed under the first segment of the body. The 

 young larva is white, but soon becomes olive colored and slimy. 

 The last time it molts it elongates, loses its slimy appearance and 

 becomes clear yellow or reddish yellow, and soon crawls or falls to 

 the ground, buries itself from one to four inches and changes to the 

 chrysaUs stage. It does not spin a cocoon but forms an oval cavity 

 in the earth and cements it together with slime, thus forming a 

 chamber within which it transforms. The larva is shown natural 

 size and enlarged in Fig. 28. 



LIFE HISTORY. 



The flies appear the last of May or early in June and deposit 

 their eggs as described above. The eggs hatch in about two weeks. 

 The slugs change their skin four or five times and come to maturity 

 in about a month, crawl into the ground, change to the chrysalis state, 



