456 MAINE AGRICULTURAL EXPERIMENT STATION. IQI2. 



This species was imported from Europe and distributed in 

 Massachusetts about 6 years ago by the entomologists engaged 

 in the gypsy and browntail moth investigations. Since that 

 time the insects have gradually spread until now it has a wide 

 distribution in northern New England. The females (figs. 483 

 and 499) have the habit of hibernating in the winter webs of 

 the browntail moth, not. attacking the caterpillar stage but are 

 parasitic upon the browntail moth pupae. 



FIG. 483. Monodoiitomcrns aercus. Greatly en- 

 larged. (After Howard and Fiske, 1911). 



As a period of about 2 months must elapse from the time 

 of the escape of the parasites from the winter webs until the 

 caterpillars of the browntail moth pupate, the little parasite 

 must live in the open during the interval. There seems to be 

 but one generation a year. The female deposits her eggs in 

 the browntail moth pupae in June, the developing young feed- 

 ing internally. When mature they escape from the pupae, the 

 females in the fall seeking shelter in the new winter nests of 

 the young browntail moth caterpillars. 



Measures for protecting the parasite. The present method 

 of destroying the browntail moth nests in midwinter while 

 effect've in killing the caterpillars, also destroys these parasites 

 if present. A modification of this method could well be made 

 by which the parasite is allowed to escape before the destruc- 



