39 



111 August the lice desert the leaves and new twigs and return to the 

 larger branches and trunk where they soon settle themselves in crevices 

 of the bark. At this time they secrete a great deal of honey-dew which 

 attracts ants and other insects, and gives off curiously enough a pun- 

 gent odor which Mr. Jack states is noticeable where large numbers of 

 the coccids are at work, but which we have not noticed at Washington, 

 probably on account of the comparative scarcity of the lice. 



This settling into the crevices of the trunk and limbs is purely for 

 hibernation and is not a permanent fixture, as when Mr. Jack took some 

 branches into the house in December they became quite active, moved 

 about the limbs and escaped to different parts of the room. 



As warm weather comes in the spring they begin moving once more, 

 the females cast their last skin and the males form their cocoons. The 

 adult males issue about May 1, and while still in the pseudimago state, 

 were observed both in Cambridge and at Washington in many cases to 

 copulate with the females. The fully developed males are seen ii: abun- 

 dance a few days later 5 the great majority of the late ones issuing from 

 their cocoons with the wings fully expanded and the anal filaments 

 complete. Indeed the long filaments protrude from the cocoon and by 

 laying hold of them the insect can be pulled out. It issues naturally 

 backwards as do (he males of other Coccidse. 



Soon after copulation the females fix themselves permanently and the 

 males disappear. This occurs the latter i)art of May. The females at 

 this time are attached mainly to the trunk and larger limbs. From this 

 stage (the impregnated female) the secretion of honey dew is more pro- 

 nounced than from the young females described in an earlier paragraph. 

 It is given off in minute drops, which, according to Mr. Jack, are plainly 

 visible while falling in the bright sunlight. The trunk, branches, and 

 lower leaves are blackened, and many ants, wasps, and flies, as web as 

 some beetles, are attracted. 



The young lice begin to hatch in from three to four weeks after im- 

 pregnation, and thus the life round is completed. 



Mr. Jack's original specimens were found upon Ulnius fulva in the 

 Arnold Arboretum near Boston, and he afterwards found the species 

 quite widely distributed in the vicinity of Boston, occurring upon U. 

 americana and JJ. racemosa as well as upon the European species, U. 

 monfana and U. campestris. He found it more common on the American 

 species than upon the European, and more abundantly upon U. fulva 

 than upon U. americana. Upon the latter species he found that the 

 Coccids preferably lefi the coarse bark of the trunk and ascended to 

 the higlier parts of the tree. 



In Washington specimens have been found upon the Department 

 grounds in considerable numbers only upon one of the varieties of the 

 European Ulmus monfana (probably" var. rubra), only occasional speci- 

 mens being found upon U. campestris and the American si)ecies grow- 

 ing side by side with U. monfana. U.fnlva, which is so badly infested 



