The European Elm Scale 7 



autumn. Scattered twigs, dead and dry in midsummer and covered 

 with wilted leaves, autunm colors on the lower limbs long in advance 

 of the proper time; these are the surest signs of GoSsyparia spuria 

 in destructive numbers. 



Often, even in midwinter, one can pick out the infested elms at a 

 glance, for the wilted leaves on branches which died in midsummer do 

 not fall, but hang on the twigs until the following March. 



THE LAEVAE IN WINTER 



As this Bulletin aims primarily to detail methods of destrojdng 

 the winter stages of this insect, we will begin with an illustrated ac- 

 count of its appearance during the winter months. In midwinter it is 

 an easy matter to find on an infested tree great numbers of such in- 

 sects as those shown on Plate I, closely adhering to the bark of the 

 lower limbs, especially on the underside. At this season these insects 

 are all dead and dry; they are the female scales of the previous 

 summer. 



Their progeny, the hibernating larvae, are not so easily seen, owing 

 to their small size and to their grey color which is much like that of 

 the bark on which they rest ; stiU without seeing them one may dem- 

 onstrate their presence by running the thumb along the bark and 

 crushing them, leaving the bark and thumb stained as with tiny streaks 

 of blood. The accompanying photographs are magnified illustrations 

 of the hibernating larvae. Plates II and III. 



A few larvae hibernate within the semi-cocoons of the dead females 

 or in rings around them, Plate IV ; some are scattered over the twigs 

 on buds and leaf -scars, Plate II ; many occur in rings about the bases 

 of small twigs, Plate II; others occur in large patches on the under- 

 side of limbs whose bark is smooth and green, Plate III; very many 

 are to be found in long rows between the projecting ridges of cork 

 on the younger branches of infested cork elms. Cracks in the rough 

 bark of the larger and lower branches of both the cork elm and the 

 American ebn are often crammed full of hibernating larvae, Plates II 

 and III. 



THE MALE INSECT 



The winter larvae remain fixed in one position until spring, when 

 they begin to complete their growth and become sexually mature. 

 In 1907 the first signs of maturity were observed early in March, 

 when eighteen more or less complete cocoons were found. The male 

 cocoon is oblong, about one-sixteenth of an inch long by half as wide. 

 At the anal end there is a horizontal slit through which the cast skins 



