THE EUROPEAN ELM SCALE IN THE WEST. 9 



of trilocular pores (PI. Ill, F). These are presumably what produce the wax 

 filaments ou some males. 



There are two forms of the male, winged and wingless. The winged form 

 (PI. II, D) has full-sized wings folded over the dorsum when not in use, while 

 the wingless form (PI. II, G) has only short wing pads. The body of the wing- 

 less form is occasionally broader than that of the winged. There are, moreover, 

 all grades between these two extremes, having all sizes of malformed wings. 

 Two wax filaments, borne on the anal lobes, extend posteriorly and equal the 

 length of the body in perfect males. These also vary in length, however, and 

 may be present or entirely lacking on either the winged or wingless forms. 



LIFE HISTORY AND HABITS. 



In the spring after mating the female scales are found to con- 

 tain a few eggs. By the time they have completed their semicocoons, 

 however, they are well filled with eggs and have increased consid- 

 erably in size. 



OVIPOSITION. 



The eggs remain in the body of the adult female until the embryos 

 are about to hatch. As each embryo becomes fully developed the 

 egg is expelled ventrally from near the tip of the abdomen. They 

 are thus laid in a sort of pocket, being protected by the body of the 

 mother and the surrounding fringe of wax. 



Each female is capable of laying a large number of eggs. Adults ex- 

 amined on July 5, 1919, after having laid for some time, contained from 

 97 to 138 eggs. Professor Doten, of Nevada, reports having counted 

 60 to nearly 300 dead larvae, which had been unable to escape from 

 under different females. A drawing of the ovaries of an adult 

 female by R. E. Snodgrass (20, fig. 19) , would indicate a still larger 

 number. He figures over 200 on one branch of the oviduct, making 

 a total of approximately 425 eggs from one female. This would 

 indicate that the rate of increase is quite large, yet not as great as 

 that of many other scale insects. 



The eggs are laid slowly, covering a considerable period of time, 

 and only during the warm part of the day. One female observed 

 laid 16 eggs in 5| hours, or 1 about every 20 minutes. The larvse 

 hatch from these eggs about 40 minutes later and are ready to crawl 

 away in another half hour. 



It has several times been reported that the adult females give 

 birth to living young. These misstatements are probably due to the 

 fact that the eggs hatched very soon after deposition and were not 

 seen by these observers. 



LARVAE. 



Newly hatched larvse are active and soon seek a place for attach- 

 ment. Some attach themselves to twigs and branches, while a large 

 majority of them migrate to the leaves, where they settle on both 

 the upper and lower surfaces along the midribs, the pubescence of 

 the leaf -veins affording them some protection. (PI. V, A.) They 

 remain in these positions until fall. By this time they are second- 

 stage larvse, having undergone their first molt about six weeks after 

 hatching. 



