DEVELOPMENT OF COPIDOSOMA GELECHI/E. 337 



pear-shaped, while others are fusiform, with various gradations 

 between these two general types. The galls occur at different 

 heights on the stem, but the vast majority of them are located at 

 or near the base of the stalk (Fig. i). Their position is un- 

 doubtedly determined by the location of the point at which the 

 larva penetrates the young shoot. If this point is located toward 

 the base of the young stalk, the gall will naturally appear near the 

 base of the fully grown plant; but if it is located in or near the 

 terminal bud, the gall will appear some little distance up on the 

 stem. Occasionally two galls are found on the same plant (Fig. 

 8). A few cases have been observed in which the gall was located 

 at the tip of the terminal bud, producing a stunted plant without 

 a central, flower-bearing stalk. With these few exceptions, the 

 gall of G. salinaris does not seem materially to affect the growth 

 and vigor of the plant. It is true that many galls are found on 

 plants that are apparently stunted but such dwarfing is to be 

 attributed to the adverse conditions under which the plant 

 sometimes grows. In regions that are very much exposed to 

 the wind, like the banks along the coast, many of the goldenrods 

 are small and clearly dwarfed; but this condition applies as well 

 to the plants that are free from galls as to those that are infected. 



The habits of gall making are similar in the three common 

 species of Gnorimoschema, although the following differences may 

 be pointed out. G. gallceasteriella produces a triangular gall at 

 the top of the dwarfed or stunted stems of Solidago ccesia, S. axil- 

 laris, S. latifolis, and Aster divaricatus - 1 The form of the gall 

 differs somewhat with the plant. The gall of G. gallaesolidaginis 

 may occur toward the top of the stem, but usually it is located 

 just below the middle, especially is this true of the galls on S. can- 

 adensis. The galls of this moth do not dwarf the plant. The 

 condition of the galls of G. salinaris on the marsh goldenrod has 

 already been described. They occur nearer the base of the 

 stem than do those of last species, and like the latter there is 

 little or no tendency to dwarfing the plant. 



The larvae secured from the galls collected between June 12 

 and 15 varied from 3 to 8 mm. in length. Beginning with the 

 middle of June, the young caterpillars grow rapidly, doubling 



1 Part of these data were kindly furnished the writer by Dr. T. M. Forbes. 



