389 



been its original food plants. This very general failure of development 

 from the egg, if normal, will detract somewhat from the injurious char- 

 acter of the insect. The severing of the terminal twigs is, however, 

 the principal damage after all, since the work of the larva, as will be 

 indicated below, only causes the death of three or four inches more of 

 the twig. 



In the twig in which successful development had taken place, the 

 larva had worked down from the tip some 3^ inches, eating out the 

 entire pith and inner layer of wood, leaving only a very thin shell. The 

 interior of the twig was densely packed with the larval excrements 

 down to within three-fourths of an inch of the base of the burrow, where 

 the larva had hibernated in a delicate cocoon. The cocoon is a little 

 over one-half an inch long, and consists of a very slight silken lining 



Fig. 43.— Phyllaecusflaviventris: a, larva; b, antennfe and mouth-parts of same; c, dorsal view of tip 

 of abdomen; d, lateral view of same ; e, pupa;/, larva in twig in hibernating cocoon, a, e, enlarged; 

 6, c, d, greatly enlarged; /, natural size (original). 



of a portion of the burrow. A section of the burrow, showing the 

 cocoon and contained larva, is given in the accompanying illustration 

 (Fig. 43/). 



The larva passes the winter practically unchanged in this cell, and 

 at the time of examination had not transformed, although pupation 

 was near at hand, as indicated by the fact that the compound eyes 

 were already showing through the head. The larva is a little over half 

 an inch long, and is creamy white in color, with the mandibles and 

 labrum brown, darkest at tips, and the area back of the base of the 

 mandibles, together with the tips of the antenna^ maxillie, and horny 

 tip of abdomen somewhat lighter brown. The peculiarities of struc- 

 ture of the larval mouth-parts, and the peculiarly spiny projection 

 terminating the body, are indicated in the accompanying illustration 

 {Fig ^3h, c, d). 



18391— No. 5 3 



