236 MAINE AGRICULTURAL EXPERIMENT STATION. I9IO. 



mens examined August 4, 1906. Measurements from balsam 

 mounts. 



Habitat, — Pupae developing in woolly bunches on trunk and 

 branches of young elm together with apterous viviparous form 

 just described. 



Maine collection number, Aphid 95-06. 



f generation, true sexes. The minute apterous ovi- 

 parous females are born with a beak which is lost with the first 

 (and only) molt. They have a 5- jointed antenna. Total length 

 of body 0.8 mm. This form lays but a single egg. The ap- 

 terous males are but 0.55 mm. long and their bodies are slender. 

 Their antennae and legs are relatively much longer than those 

 of the female. Antennae are 5-jointed. Mature male without 

 beak, this being lost at molt. Described from types taken Sept. 

 23, 1908. (Figs. 161, 162). Maine collection number, 89-08. 



The original description of this insect is as follows : 



"The Woolly Elm-Tree Louse — Eriosoma ulmi, n. sp. 

 (Homoptera Aphidae.) 



"The White Elm is subject to the attacks of a woolly plant louse be- 

 longing to the very same genus as the preceding. This insect appears 

 to be quite common in our State as well as in Illinois, for I have known 

 several elm-trees on Van Buren street in the city of Chicago to be killed 

 by it, and every tree of this description, around the court house in St. 

 Louis v^^as more or less affected with it last summer. The lice congre- 

 gate in clusters on the limbs and the trunks, and cause a knotty vmnat- 

 tiral growth of the wood, somewhat similar to the knots produced on 

 the roots of the apple-tree by the other species. They are mostly found 

 sunk in between the crevices formed by these knots, and the punctures 

 of their little beaks cause the sap to exude in the shape of little silvery 

 globules, which may generally be found dispersed among the knots. The 

 down or woolly matter is secreted by them from all parts of the body, 

 but especially from the posterior part of the back. It is of an intense 

 white color, and is secreted in such profusion that it usually covers and 

 hides the lice, and when they are numerous, gives the limbs from a 

 distance the appearance of being covered with snow. They make their 

 appearance during the latter part of May, and by the latter part of June 

 the winged individuals may be found mixed up with the larvae and 

 pupae. I have experimentally found that a washing with a weak solution 

 of cresylic acid soap will kill them instantly, and they are thus easily 

 exterminated. They are also preyed upon unmercifully by the larvae of 

 an undescribed species of Lacewing fly (Chrysopa eriosoma of my MS.). 



"Eriosoma ulmi, N. Sp. — Color dark blue. Length to tip of closed 

 wings, exclusive of antennae, 0.12.* Wings hyaline, three times as 



* i. e. inch. 



