266 QUARTERLY JOURNAL. 



gall, to the apex of the brittle horn at its summit, within which 

 canal the larva lies. A beautiful provision of nature is here observ- 

 able. The extreme tip of the horn at the top of the gall is so 

 slender and brittle, that it is easily broken off by the slightest 

 touch of the wing of a bird, or a contiguous twig agitated by the 

 wind. It is therefore rare that it is found entire. But in break- 

 ing off, the edge of the part below, which thenceforth forms the 

 apex of the horn, generally splits into several short, slender, elas- 

 tic teeth or valves, the points of which converge so as to leave but 

 a slight orifice into the canal below. The inclosed maggot, when 

 ready to leave its cell, easily crowds these valves apart, and makes 

 its exit — w^hilst any enemy attempting to insinuate itself into this 

 orifice, only draws them more closely together. But that this 

 curious structure sometimes fails of accomplishing the purpose for 

 which it seems so admirably designed, will be rendered probable, 

 when we come to speak of the enemies of this insect. 



But little account is made in our country at the present day, of 

 any of our several species of willow. That which in an economi- 

 cal point of view is probably the most valuable, is the species ori- 

 ginally described by Muhlenberg, under the name of rigida. The 

 very long, wand-like character possessed by the } ounger shoots, 

 combined with the toughness and flexibility which is peculiar to 

 them, have caused this to be esteemed more than any of our other 

 native species, for the manufacture of baskets and other articles of 

 willow-work. This, and its allied species salix hicida, (Muhl.,) 

 seem to be the ones most preferred by the insect under considera- 

 tion, though it also infests two or three others to a less extent. 

 But upon our tall tree- willows it is never found — it may be, be- 

 cause their much more slender twigs would not alTord sufficient 

 nourishment for the insect, and the very slight articulations of 

 these twigs would be incapable of sustaining the additional weight 

 of these galls, without snapping off and falling to the ground with 

 the first gust of wind. Of course those twigs of the rigida or 

 American basket- willow, on which the galls are formed, become 

 worthless for the use above alluded to. Their onward growth is 

 arrested ere any of them attain that length which renders them 

 valuable, and in the course of the following summer, most of them 

 die entirely down to their origin. 



Should it ever become an object to diminish the numbers of this 



