20 INJURIOUS INSECTS OF 1904. 



head ; a few very small hairs are scattered over the body. The 

 larval life is about forty days, and when full grown it measures 

 from 1/2 to 3/5 of an inch in length. The color becomes more 

 pronouncedly pink than in the young larva. We have noted in 

 the laboratory that individuals vary in color, some even appearing 

 to have a greenish tint. There are six true legs near the anterior 

 end of the body, and four pairs of rather long fleshy legs on the 

 abdomen. With a lense one can see that each one of these abdom- 

 inal legs is provided with a circle of small hooks at the end (Fig. 

 7, colored plate). There is also a pair of so-called caudal legs at 

 the extreme posterior end of the larva. 



Little blackish or brownish spots, each bearing one or two 

 hairs, are formed over the body, three on a side in each segment. 

 At the anterior and posterior ends, the spots which are lower down 

 on the side are larger and more conspicuous than the others. One 

 spot on e;ach side, just back of the head, is formed by an incom- 

 plete ring, its circumference being broken toward the head. A 

 careful study of the colored plate (Figs. 4 and 5) will help one in 

 recognizing these details. Just back of the head (see Fig. 6 of 

 colored plate) is a conspicuous reddish brown plate or shield, 

 divided into two parts by a middle pale line. 



The larva has a pernicious habit of secreting a silken thread 

 wherever it goes. When traveling back and forth over a 

 smooth surface this results in a sheet of silken tissue of consider- 

 able strength, much like that seen in Fig. 6 in text, which illus- 

 trates the work of the worms on a piece of bolting cloth covering 

 a breding jar in our laboratory. When, however, the larvae are 

 crawling through flour or meal the result is, as many millers 

 know to their cost, a mass of flour held together by countless 

 threads, forming a webbing which clogs spouts, elevator legs and 

 other machinery to such an extent frequently as to completely 

 stop the work of the mill. (See Fig. 10 in text.) 



This larva may find its way into a perfectly clean mill in retuDied 

 sacks, iinh'ss said sacks are treated in some ivay before being placed m 

 mill. Second-hand machinery from an infested mill may harbor larvcc 

 or eggs. When full grown, which takes, as we have said, about 

 forty days, the larva crawls about restlessly until it finds a place 

 to spin its cocoon, about 1/2 inch long, within which it transforms 



