174 FIRST ANNUAL REPORT OF 



chrysalis state by eating; a perfectly round passage-way entirely 

 through the wall of the gall at its upper end. It then protects the ori- 

 fice with a secretion of liquid silk which hardens and forms a perfect 

 little plug (Fig. 96, c\) about 04 thick and 0.08 in diameter, and which 

 is so constructed that it cannot be readily displaced from without, as it 

 has a rim on its outer edge. The inner edge, however, is not so rimmed, 

 an.! the plug can be pushed away from the inside with the slightest 

 effort, for the little tenant when it shall have become fitted to leave 

 its dark and secluded tenement and soar into the air, must needs 

 make its exit through this orifice. Well may we wonder at Nature's 

 handiwork, for what consummate skill, and wonderful instinct — I had 

 almost said forethought — is here exhibited ! Can this action be but a 

 blind instinct, or has the larva a premonition of its future etherial 

 imago state and its wants? Who can answer? Our little host, not 

 satisfied with having thus protected the entrance to his home, now 

 lines its passage way, and the walls, with a delicate silken tissue, after 

 which he rests from his labors, and commences to undergo those mys- 

 terious transformations, so characteristic of his class. A gall cut in 

 two at this stage of its growth presents the appearance of Figure 96, 

 b. In two days' time the little worm has changed to a chrysalis, just 

 ■£ inch in length, rather slender and of a shiny mahogany-brown. At 

 the end of about three weeks more the chrysalis grows very dark, and 

 finally the inclosed moth bursts the skin and escapes from the gall. 



The first moths usually appear about the middle of August, but as 

 the time of egg-depositing covers a period of over a month, some of 

 the moths have not left till the beginning of October. As winter ap- 

 proaches, the stem seems to grow weak above the gall, and usually 

 bends and droops, while the gall itself shrinks and acquires a whitish 

 weather-washed appearance. It is for these reasons, and from the 

 gall being so near the ground that it does not attract the same attention 

 as the large, round gall of the Tiypeta. 



I have been acquainted with this gall for six years, and have 

 studied it closely during that time. It seems to occur qmte generally 

 over the country, and is especially abundant in the West. The first 

 published account that I can find of it in this country is that given by 

 Baron Osten Sacken, in the first volume of the Proceedings of the 

 "Philadelphia Entomological Society," page 869, where he correctly 

 describes it, as well as the puffed carcass of one of the caterpillars 

 (PI. 2, Fig. 5), caused by a parasitic Chalcis fly presently to be des- 

 cribed; but he was not acquainted with the maker of the gall. The 

 galls were received by him from Edward Norton, who resides at 

 Farmington, Connecticut. They occur abundantly around Chicago, 

 especially on the north side, in the old cemetery, which is now being 

 converted into Lincoln Park. They are equally abundant, around St, 

 Louis, while I have found the same gall on the Solidaga Missouriensis 

 growing beyond Fort Kearney, in Nebraska, and even there the worm 

 was attacked by the same parasitic Chalcis fiy mentioned above. 



