2 BULLETIN 566, U. S. DEPABTMENT OP AGRICULTURE. 



much annoyance. It is not unreasonable to suppose that this insect 

 will spread to other sections of the country and cause great annoy- 

 ance to farmers. 



A much smaller colony, which, however, has increased rapidly, 

 was reported from Seattle, Wash., in 1915. Other reports of the 

 occurrence of this earwig in the United States appear to have origi- 

 nated from one or two cases in which isolated specimens were cap- 

 tured on imported plants. 



This earwig is found all over Europe, but is seldom present in 

 extreme numbers. It is impossible to say from which of the Euro- 

 pean countries the colony at Newport originated, or how the - first 

 individuals were imported. Quantities of nursery stock arrive from 

 abroad each year upon which the importation may have been made. 



DESCRIPTION AND SEASONAL HISTORY. 1 



THE EGG. 



The female earwig lays from 50 to 90 shining white eggs (fig. 2) 

 in the ground, the eggs being about one-twentieth inch in length. 

 Forty females were mated and placed in separate 

 cans of soil for observation. One deposited 82 

 eggs between November 6 and 10. On December 

 26 a second examination showed that 30 of the 

 females (75 per cent) had deposited eggs. These 

 females do not die at once, but hibernate, and in 

 the spring attend the larvae in their early stages. 

 fig. 2. Eggs of Euro- Durjhg the previous year in a few cases eggs were 



pean earwig. En- . . . . 



larged twice, deposited in the spring, but failed to hatch. 



Mellow garden soil with a southern exposure 

 is a favorite place for egg deposition. Many hibernating females 

 and their eggs have been found from 2 to 3 inches below the surface 

 of the lawns. 



THE LARVA STAGES. 



The young earwigs, or larvae,, may be found in the ground, or at 

 night on the soil surface, about May 5. They resemble the adults in 

 general form, but have no wings and only delicate, simple forceps or 

 pinchers on the posterior extremity of the body. At first they are 

 pure white, but the color slowly darkens to a delicate olive green 

 which has a peculiar shiny appearance. About June 9 they appear 

 very dusky olive green, or even steel gray, with almost transparent 



1 The season during which these notes were gathered was rather peculiar. The entire 

 spring was so cold and wet that foliage and insects were retarded in their development 

 approximately one week. The summer was nearly normal, but was followed by a long 

 dry fall. No killing frost occurred until the second week in November, and no real 

 freezing of the soil took place until after December 1. The larval development in an 

 ordinary season would be approximately one week ahead of the dates given for 1916, 

 while the fall dates for hibernation and egg deposition usually would be from one to 

 four weeks ahead of those in 1916. 



