I 



REPORT OF THE STATE ENTOMOLOGIST I914 23 



habits makes it particularly efficient in destroying white grubs, 

 though it also possesses some undesirable traits. Blackbirds are also 

 known to feed upon white grubs. English sparrows were observed 

 last summer destroying many of the beetles in and around the electric 

 lights of Albany. 



Several parasites prey upon these insects One of the most common 

 is known asTiphia inornata Say. The oval, brown cocoons 

 of this species are about three-fourths of an inch long and may be 

 distinguished from those of an allied form by the slight neck or con- 

 striction at one extremity. These cocoons are frequently rather 

 abundant in fields which have been badly infested by white grubs. 

 Another large parasite, Myzine sexcincta Fabr., preys upon 

 white grubs and spins a cocoon similar to that of Tiphia though 

 differing in its greater smoothness and lacking the loose, fluffy coating 

 of silk. Ophion bifoveolatum Brulle. has been reared 

 from white grubs, and as there are a number of closely related 

 species, some of which are quite common, it is probable that this 

 insect and its allies are frequently very efficient checks upon the 

 white grubs. 



A large, milk-white maggot with a hard integument and black 

 mandibles was extremely abundant at Schodack in 19 12 and 19 13 

 in fields badly infested with white grubs, and upon rearing, it proved 

 to be a rather common robber fly known aS Promachus 

 fitchii 0. S. The maggots live in the soil for a period of over 

 two years and the insect evidently has a three-year cycle, which 

 would indicate an adaptation to the habits of their prey, the white 

 grubs. These beneficial larvae were abundant in a number of areas 

 where white grubs had evidently destroyed most of the grass roots, 

 though at the time of our examination very few remained alive. 

 On the other hand, places were found near by where there were 

 nimierous white grubs and comparatively few of these beneficial 

 maggots. This, taken in connection with the maggots actually being 

 seen attacking the white grubs, leaves no doubt as to the beneficial 

 habits of this comparativel}'" unknown species. This robber fly was 

 unusually abundant last summer at Nassau. A bee fly, S p a r n o- 

 polius fulvus Wied., has been reared in Illinois from white 

 grubs and has somewhat similar habits to those described above for 

 Promachus. The peculiar and striking Pyrgota undata 

 Wied. has also been reared from white grubs, but unfortunately both 

 of these last-named species appear to be comparatively rare in New 

 York State. 



White grubs are also subject to fungous attack. The white grub 

 fungous, Cordyceps ravenelii Berkl., occurs here and there 



