472 Bulletin No. 116. [August, 



does sometimes normally infest and attack insects exposed above 

 ground by their habits, burying them as a matter of instinct after 

 it has placed its egg. Tiphia has not, in fact, been studied as an in- 

 dependent species, but all the data concerning its habits and life 

 history have been gathered in the course of studies of the white- 

 grubs. 



The egg of Tiphia remains firmly glued to the back of the chosen 

 grub, and hatches in seven to ten days. The young larva breaks its 

 way out from the egg at one end, and, although it begins at once to 

 feed, it does not at first free itself from the shell, but as it grows 

 this finally splits and breaks away. When it first emerges the larva 

 measures slightly more than a millimeter in length. From our scanty 

 data it appears that it takes about two weeks to get its full growth, 

 andjhat it doubles its size in the last two days of its larval life, dur- 

 ing which it is engaged in devouring the body of its host. Previous 

 to this time it has been adherent to the skin of the grub whose fluids 

 it has lived upon. When full grown it is from two thirds to four 

 fifths of an inch in length. 



The cocoons are cylindrical ovate, from 17-22 mm. long, clay- 

 colored at first, and wood-brown or cinnamon-brown when older. 

 From our observations thus far made it appears that the larva 

 hibernates within the cocoon, not pupating until the following 

 spring. The adult emerges from a little one side of the larger end, 

 in which it leaves a ragged and irregular opening. In several cases 

 the abundance of these conspicuous brown cocoons in the earth was 

 such as to indicate an enormous destruction of white-grubs, and 

 there is no doubt that this parasite is an important agent in checking 

 destructive uprisings of these insects. 



That this wasp, parasitic on white-grubs, is itself parasitized, is 

 shown by the results of observations made on Tiphia cocooits col- 

 lected April 27, 1906, and kept in breeding-cages during the sum- 

 mer. From these emerged, July 7, 16, and 31, adult bee-flies (Bom- 

 byliidcE) of the species Bxoprosopa fascipennis, each freeing itself 

 from the Tiphia cocoon by cutting out a circular piece at the larger 

 end. The eggs from which these flies resulted were probably laid 

 on the Tiphia grub in 1905, before the cocoon was spun. 



Miscellaneous Insect Enemies. 

 Macrophfhalma disjuncta. — This little tachinid fly was men- 

 tioned in my Seventh Report as bred repeatedly from dead white- 

 grubs, but I was nevertheless uncertain that it was a parasite. Lately 

 its parasitic nature has been proven by repeatedly breeding it from 



