12 Circular 100 



ton, Clifton, Arlington, Elizabeth, Secaucus, Red Bank, and Pater- 

 son in New Jersey, as well as places on Staten Island. It is a Euro- 

 pean species and was described in 1781 by J. N. von Laichartig 14 

 under the name versicolor a which is an older name for the common 

 European Plagiodera armoricce of Fabricius. It is undoubtedly 

 well established in New Jersey and has been for several years. 



The foliage of poplars and willows is destroyed by both beetles 

 and larvae, the beetles eating the entire leaf tissue, and the larvae 

 the lower epidermis. The beetles hibernate during the winter under 

 loose bark or in crevices in the bark, and appear in New Jersey in 

 late April or early May. After feeding they begin oviposition, this 

 operation continuing through the greater part of May. By early 

 June, the adults of this brood had apparently disappeared and all 

 eggs had hatched. The first adults developing from this brood of 

 eggs were noted about June 10, and continued to appear until the 

 early part of July. The first eggs were deposited by the second 

 brood of beetles about July 1, and oviposition continued until the 

 early part of August. The adults developing from this brood of 

 eggs began to appear in the latter part of July and continued until 

 late August, after which time, after feeding and copulating, they 

 disappeared from the plants, having gone into hibernation. Thus 

 there are two complete broods of the insects in addition to the 

 hibernating beetles each season. There are five larval stages re- 

 quiring from 3 to 6 days each and about a month's time is required 

 for a complete cycle. 



The lemon yellow eggs are laid in irregular masses of from 

 12 to 30, the average being about 19. Each egg is smooth, narrowly 

 oval in outline, with broadly rounded extremities and measures 

 0.95 mm. loug by 0.45 to 0.55 mm. broad, being inclined at an angle 

 of 30 degrees. As a rule, only one mass occurs on the under-side 

 of a leaf. The eggs hatch in from 3 to 5 days into brownish black 

 larvae which feed at first in colonies on the under surface. When 

 full grown, at which time the larva is about 5 mm. long, it attaches 

 itself usually to the under leaf surface by means of a sucker-like 

 disc at the anal extremity and changes to the pupa, which rests 

 with its posterior end within the cast skin of the larva. This stage 

 lasts from 2 to 3 days. The pupa is yelloAvish-brown in color with 

 dark spots and markings. The tubercles on the sides of the thorax 

 and abdomen of the larva contain eversible hypodermal glands which 

 are operated when the larva is irritated, giving off a characteristic 

 odor. This species can undoubtedly be easily controlled by timely 

 treatments of arsenate of lead applied to the under-sides of the 

 leaves. 



14 Von Laichartig, J. N., 1781. Verzeichniss und Beschreibund der Zyroles 

 Insecten. p. 



