1907.] NATURAL SCIEN'CES OF PHILADELPHIA. 7 



wax threads from the head, thorax and sides of the abdomen also 

 grow very rapidly, so that, with the aid of the wings, both louse and 

 eggs are almost completely hidden in two or three days. Egg laying 

 proceeds very rajiidly. From numerous counts made by the writer, 

 and others made for me by Mr. G. P. Weldon, I extract the following: 

 Seven large egg clusters, selected July 16 and 18, 1904, ran as follows 

 in numbers of eggs: 96, 111, 127, 133, 136, 151, 155, an average of 

 approximately 150. Seven medium egg clusters from leaves of red 

 fir, where the lice had been located but 48 hours, gave counts as follows : 

 63. 66, 70, 74, 75, 88, and 104. Seven selected large egg clusters, where 

 lice had been located only 48 hours, ran as follows: 90, 111, 126, 131, 

 133 and 150. ^Vhen we consider the large size of these eggs as com- 

 pared with the females that lay them, it seems to me this is a develop- 

 ment of reproductive tissue that is simply marvelous. These winged 

 lice seem never to change their location after they have once inserted 

 their beaks and begun to lay eggs. 



Occasionally one of these lice can be found feeding and laying eggs 

 upon leaves of the blue (silver) spruce, but it is quite rare. By enclos- 

 ing thousands of the lice in paper sacks upon twigs of this tree, I got 

 enough to locate and lay eggs so as to get a few counts. The lice did 

 not seem to be thrifty, however, and the number of eggs laid was 

 smaller. Four lice located 48 hours on blue spruce deposited 16, 17, 

 19, and 36 eggs respectively. Seven of the largest patches where the 

 lice had been settled 72 hours ran in numbers as follows: 33, 50, 53, 

 55, 74, 84, and 96; an average of about 64, or less than half the average 

 number in large egg clusters upon red fir. On July 20, 1906, it required 

 careful search to find one of these lice located upon blue spruce, w'hile 

 the red firs near them had one or more of the lice on nearh' ever}' leaf, 

 and many leaves were loaded with five or six of them (PI. II, fig. Ci 

 and D). 



Lice continue to emerge from the galls till about July 25, and all 

 apparently are females. 



The eggs laid by these winged females hatch in from six to seven 

 days. Eggs laid July 12 began hatching July IS, and were all hatched 

 on the 19th. The lice from these eggs are yellow at first, but soon 

 become nearly black in color fringed with short wax threads similar 

 to variety coweni (PI. Yl, figs. A, A^). Many of the lice hatching at 

 this time remain beneath the dead bodies of the winged females, which 

 die soon after the eggs are laid, but most of them scatter about over 

 the leaves and come to rest chiefl}' upon the older leaves near the bases 

 of the small twigs. Here they insert their set* and remain till spring 



