REPORT OF THE STATE ENTOMOLOGIST I914 I9 



work. At the outset it should be stated that these grubs, at the 

 time the injury was most apparent, were about a year old. They 

 had hatched from eggs laid the preceding June and were destined 

 to live a second winter as grubs and change to beetles in August 

 or September 19 13. The adults, though fully developed in late 

 summer or early fall of that year, did not appear above ground till 

 May and June 19 14. 



A number of sample diggings were made in the spring of 19 13, 

 for the purpose of ascertaining the conditions of the insects and the 

 relative mortality. Numerous full-grown grubs were found, as 

 many as nine being uncovered in an area of approximately one and 

 one-half square feet. A few adults ofLachnosterna fusca 

 Froh. occurred with the white grubs and there is a possibility that 

 some individuals of this species may complete the life cycle in two 

 years, though the developments of the past season (19 14) conclu- 

 sively establish a three-year cycle as the normal. 



The most interesting development was the discovery of num- 

 erous large Dipterous maggots in 191 2. These preyed upon the 

 white grubs and were carried through the season of 19 13, and 

 adults were secured in the spring of 19 14, showing the species to 

 have, like its host, a three-year life cycle. This efficient enemy of 

 the white grubs proved, upon rearing, to be a common robber fly 

 known as Promachus fitchii O. S. 



Observations in 1914. The abundance of beetles in 191 1 and the 

 occurrence of many white grubs in the soil in 191 2 and early the 

 following season, made it comparatively safe to predict a large 

 flight for this year. About May 14th, the beetles began to be abund- 

 ant in and about Nassau, and on the i6th to the i8th they were 

 common on the streets and reports of unusual numbers began to 

 be received. Similar conditions were noted at Clinton Heights 

 and on the Capitol grounds at Albany. Collections May 19th at 

 Nassau resulted in taking in the early evening Lachnosterna 

 fraterna Harr. almost exclusively from bushes on low ground 

 near a stream, while later in the evening almost equal numbers 

 of this species and L. fusca Froh. were collected under electric 

 lights somewhat remote from the above-mentioned low ground. 

 There were marked differences in the abundance of the insects 

 about various lights, even in cases where there were approximately 

 equal areas of grassland near by, though in a general way the pests 

 were more abundant around the outlying village lights. 



The feeding of the beetles, while injurious to trees, may be taken 

 advantage of to some extent to indicate the approximate amount 

 of injiiry which may be expected from the grubs the following season. 



