856 EXPERIMENT STATION EECOED. 



" The insect is at least 2-brooded in tliis locality ; the injury by the first brood 

 of larvie becoming manifest by the middle of June, at which time the larvie 

 are approaching full size and the older ones are already going into the pupa 

 condition. The pupal stage is of short duration and the moths commenced to 

 emerge by June 28 and continued coming out for nearly a month. The majority 

 of the moths had emerged by July 10. In late July and early August the tiny 

 larvje of the second brood may be found working in the terminal buds, and, as 

 this brood develops, the previous injury is duplicated. The egg of the moth is 

 a small, flat, yellowish object and seems to be usually deposited near the 

 extreme end of the young tips so that the larvse on hatching burrow immediately 

 into the tender bud, and, as it develops, they form a cavity from 1 to 3 in. in 

 length. When full grown, the insect pupates near the terminal end of the 

 infested tip. This burrowing causes the death of the tip. and, as the needles 

 rapidly turn brown and drop off, the injury becomes very conspicuous. On the 

 National Forest the princi])al injury occurs on jack nine but the Scotch pine 

 and western yellow pine are also affected. A considerable amount of parasitism 

 is present among the tip moths, a small, black ichneumon fly and a chalcis fly 

 being the principal parasites." An entomophilous fungus was also at work 

 during 1910. 



A new sawfly enemy of the bull pine in Nebraska, M. H. Swenk (Nehraska 

 Sta. Rpt. 1910, pp. 3-33, pgs. 18).— In May, 1910, reports were received to the 

 effect that the pines east of Crawford were being stripped of their needles by 

 worms. It was found that the region of greatest infestation lay in an elevated 

 portion of Pine Ridge, east of the town of Belmont. 



Specimens received and bred to adults were found to represent a new species 

 of sawfly, closely related to Diprion (Lophyrus) toicnsendi. Rearing cage ex- 

 periments showed that the larvse, while preferring the foliage of the bull pine 

 or rock pine (Pinus scopulorum), also fed eagerly upon needles of the closely 

 related Austrian pine (P. austriaca) and to a limited extent iipon the Scotch 

 pine (P. sylvestris) . 



The larvae of this sawfly are conspicuously gregarious and occur in bunches 

 of from 25 to 50 or 75 among the needles at the tips of the branches. The 

 larvse which hibernate in the trees become active in the spring and are nearly 

 full grown by May 1, at which time the tops of the trees have been conspicu- 

 ously denuded. By this time they stop feeding to any great extent in the day 

 time and soon thereafter begin dropping to the ground to spin up. At the 

 time of the author's first visit on May 29, the larvae were very abundant on the 

 trees but were said to be much less so than they had been a week or 10 days 

 previously. By June 10 they had almost disappeared from the trees. In 

 rearing cages the first larva spun up May 25 and the next on May 30; this 

 continued until June 27 when the last of 69 larvse spun its cocoon. 



Pupation apparently begins in early June and extends over at least a month. 

 The first adults were found in the field on June 10 and by July 7 and 8 the 

 adult females were common on pine tips. A small clump of young larvae of 

 the new generation was found in the field as early as July 8, these probably 

 representing exceedingly accelerated individuals, the progeny of adults which 

 issued in early June. By October 27 the larvse had become half grown and had 

 made very obvious defoliations. About this time they apparently cease active 

 feeding and do not grow perceptibly until the following spring. Hibernation 

 takes place in 2 distinct ways, namely, as half grown larvse in the trees and 

 as fully developed larvse tightly packed in cocoons in the ground. The larvse 

 which hibernate in cocoons in the ground, at least in part, are thought by the 

 author to be those which have spun up after having become full grown the 

 preceding season. 



