REPORT OF THE STATE ENTOMOLOGIST I913 2$ 



resulted in securing five full-grown grubs and two Tiphia cocoons. 

 A third digging comprising about i square foot produced only three 

 grubs.. The occurrence of a few beetles in these and other diggings 

 suggests the possibility that a few individuals of L. fusca may 

 complete the life cycle in two years, as Davis has found to be the 

 case with L. t r i s t i s Fabr. 



The most interesting development of the season was on the 

 farm of Mr Jesse Weaver in East Schodack. Here were found, 

 April 24th, large numbers of a stout, white maggot, the larvae 

 of a bee fly or a robber fly. The abundance of this enemy is 

 evidenced by the following data. The turning of four furrows each 

 a few feet long and in a field badly infested with white grubs the 

 preceding season, resulted in finding one adult, Lachnosterna 

 fusca, nine white grubs, four Tiphia cocoons and twenty-six of 

 the Dipterous maggots. The white grubs and the maggots occurred 

 at an approximate depth of 4 to 6 or 7 inches. The above numbers 

 are fairly indicative of the relative abundance of the grubs and 

 maggots. The latter were mostly moderately large and stout, 

 though a few were about half the size of the larger ones. Prac- 

 tically all were in a vigorous condition and were most abundant in 

 portions of the field which had been very badly infested by white 

 grubs the preceding season. They were presumably important 

 factors in destroying these grass pests. 



Similar conditions obtained June 18th in an adjoining field belong- 

 ing to Mrs Kane. There was, as in the other case, a marked 

 restriction of the maggots to grass areas which had been seriously 

 affected by white grubs the preceding season and, as a rule, where 

 maggots were numerous few white grubs were to be found, while 

 the latter were relatively more numerous where there were no 

 maggots. The most obvious explanation of this condition is that 

 the parent flies oviposited freely in the badly infested areas, and 

 as a result most of the white grubs were destroyed, while the 

 sparsely infested parts of the field were largely overlooked by the 

 flies, and as a consequence the grubs were relatively more abundant 

 last spring. The probability of these maggots preying upon white 

 grubs was well shown by the fact that in one box a maggot was 

 observed actually attached to a white grub, while in other instances 

 there was a marked mortality among white grubs confined in breed- 

 ing jars in which there were a number of these Dipterous larvae. 

 The proportion of the two forms is shown by a collection of 

 seventy-nine maggots and fifty-five white grubs as a result of fol- 

 lowing the plow for less than two hours. There appeared to be 



