i6 I' I lie APiM.i': r.K.Ai' ijoiM'i:!^ 



The egg blisters tlieniselves are usually very slightly crescentric 

 in form, though often simi)ly elongate-oval, and at one end of each 

 there is an inconspicuous short, slanting incision or o]KMnng, where the 

 ovipositor was passed into the bark at the time of oviposition. 



The egg inside of these blisters is not imbedded in the bark as 

 deeply as are those of other s])ecies, the blisters of which are found 

 commonh' on apple trees. They are covered by the epidermis and 

 the corky portion of the bark, and only a thin layer of cortical 

 parenchyma. The eggs of the other species have a thicker layer of 

 cortical parench}ma between them and the corky portion of the outer 

 bark. 



The eggs themselves are of about the same length as the pockets 

 which cover them, but they measure somewhat less than .2 mm. in 

 greatest width. They are elongate and nearly circular in cross section, 

 slightly curved from end to end, of about equal width throughout their 

 length, and rounded at their ends. They have very delicate, transparent 

 shells, and it is difficult to open one of the blisters so as to expose one 

 without crushing or puncturing it. ( )ne of these eggs may be most 

 easily uncovered for examination by first cutting into the bark with a 

 fine scalpel, on both sides of the egg l)lister, and then joining these two 

 cuts at some little distance beyond that end of the blister which shows 

 the incision of the ovipositor. The covering of the bark may then be 

 lifted up from the egg, beginning at the place where the two cuts are 

 joined, with a pair of tweezers. 



The end of the egg which is nearest t<i (he o])ening made b\- the 

 ovi]:)ositor always protrudes slightl\- through the cortical parenchyma 

 covering, and is cemented to the under surface of the overlying corky 

 layer. The cortical parench\nia layer will often rupture very easily 

 and allow the ci^g to be pulled away readily with the corky layer. Fig. 5 

 shows one of these eggs ])ulle(l oul ir ibis wav. and still arlhering to the 

 corky layer. 



These eggs, when first examined, were filled with clear, semi- 

 trans])arent liquid material, which was broken up considerably into 

 small globules. When examined, November 2nd, manv of them w^re 

 still in this cond'tion. but many were slightly clouded in s]-)ots on the 

 inside, and in some the young nymph, though still very small and shape- 

 less, could be seen to have already taken form. These nymphs were at 

 that time wdiite in color, and they occupied but a very small part of the 

 interior of the egg. They coidd be seen to move slightly now and then. 

 Dr. Franklin examined carefully and measured certain egg-blisters on 

 the small branches of elm trees, which were similarlv located with re- 



