256 EXPERIMENT STATION EECORD. 



Iowa there are four generations, counting the generation \yhich hatches from 

 the egg early in the spring as the first. Leaf hoppers are found on foliage 

 as late as the middle of October, although most of them are gone by that time. 



Tripheleps inskliosus, which attacks the nymphs, is said to be the most im- 

 portant natui'al enemy. Occasionally larvae of the lace-winged flies attack the 

 hoppers. A mite nymph has been found attached to the thorax of an adult 

 hopper and an empid fly (Draijctis sp.) has been observed with its proboscis 

 inserted in the under side of the abdomen of iiymiths. 



" Experiments during 19<J9 showed that the dipping of nursery stock in sim- 

 ple soap solutions was effective in killing practically all of the leaf-hoppers on 

 the trees dipi)ed. For southern Iowa the best time fur this dipping is about 

 June 20 and July 20 ; for central Iowa, the 25th ; and for northern Iowa, the 

 30th. The June treatment is the more important one. Trees might also be 

 treated about the same time in August. . . . Solutions of whale-oil soap and 

 white laundry soap were found to be very successful as dips. The first was 

 used 1 lb. to S gal. of water, and the second 1 bar (about 10 oz.) to S gal. 

 To be effective this dipping must be thoroughly done, and well timed, so as to 

 catch the insects when they are most susceptible." " Spraying with kerosene 

 emulsion for the first generation of leaf-hopi)ers. which work on the lower 

 leaves of the nursery trees, was fairly effective. The spraying for the second 

 generation was not so effective, on account of the badly curled terminal leaves 

 at that time. Other materials were also used, but with similar results. . . . 



" It has been suggested that the hoppers might be attracted to light and 

 caught in lantern traps. Observations made at Ames show that this attraction 

 is not great enough so that it could be used in this way." 



A bibliography of the literature relating to this species is appended. 



Chermes of Maine conifers, Euith M. Patch {Maine 8ta. Bui. 173, pp. 

 277-308, pis. IJf). — Seven siiecies of Chermes, 6 of which are gall forming, are 

 here described and figured. A discussion of the economic aspects of the two 

 more important si)ecies has been previously noted (E. S. R., 22, p. 552). 



The pine leaf Chermes, C. pinifolicx; (=C ahieticoletifi) , was found in great 

 abundance at Orono on June 16, at which time most of the individuals were 

 dead with a large cluster of eggs beneath the wings. On July 5 at Milo, dead 

 individuals were very abundant on the needles of white pine, as many as 16 

 adhering to a single needle. By June 21 fresh Chermes were present on the 

 needles of white pine everywhere in the neighborhood of Orono. The disap- 

 pearance of the emerging abieticolens from the spruces coincided exactly in time 

 with the appearance of pinifoliw on the white pine. On June 22, galls from 

 the black spruce were placed in a cage with fresh twigs of various conifers. 

 Three days later more than 200 individuals were found to have settled and 

 deposited eggs on the white pine. On July 3, young were observed to be hatch- 

 ing out in conspicuous numbers. These young of the migrants settled at the 

 tips of new pine twigs, where by the latter part of July their presence was very 

 conspicuous on account of the \Ahite waxy secretion, which gives a woolly 

 appearance to the infested portion. Where the infestation is heavy, it causes 

 a yellowish, sickly appearance of the new gx-owth, which is considerably 

 stunted. C. pinifolioe found on spruces the middle of May are thought to be 

 the return migrants from pine, although the actual migration has not been 

 observed. The data here presented indicate that either the time which jrini- 

 foliop spends on the spruces is very short. 4 to 6 weeks, or that a 2-year cycle is 

 required. A bibliography accompanies the account of this species. 



C. abietis has been abundant annually on the Norway and white spruces ;it 

 Orono. The life cycle based upon the author's observations is as follows: 

 " Galls oi^en about mid-August and fully grown pupae emerge and molt within 



