The White Grub of the May Beetle. 19 



devour it — species of the rapacious Carabidce, probably Calosoma 

 calidum and others, but their names have not been recorded. 



A Parasite. — While many insect attacks are restrained through 

 the beneficent aid of other insects, which, in our gratitude, we are 

 apt to regard as specially com- 

 missioned to perform this duty 

 for our protection, thus far we 

 know of but a single parasite 

 which is waging warfare upon 

 the white grub. This insect ""* a c & 

 was described and figured by 1 ^' ^^^^^Ir^^' 



Professor Eiley, in his Sixth Report on the Insects of Missouri 

 (1874, pp. 123, 124), as the white grub parasite — Tiphia inornata. 

 It is shown at a in the accompanying figure. It is one of the 

 digger-wasps, and the ease with which these creatures are able to 

 burrow in the ground enables this one to discover the grub in 

 its concealed retreats, and by depositing an egg upon the 

 body, to provide for its progeny its needed food, and to 

 insure the death of the attacked grub. The parasitic larva, 

 shown at c, having matured, it incloses itself for its changes 

 in " an egg-shaped cocoon of a pale golden-brown or buff color, and 

 with a soft exterior surface, in touch as well as color. * * * 

 Upon cutting this cocoon open, it will be found to consist of about 

 a dozen delicate layers, the outer ones soft and loosely spun, the 

 inner ones more and more compact and paler in color." The cocoon 

 is shown at d in the figure. Their presence in the ground (from 

 the above description and figure they may be easily recognized) 

 serve to show the parasitic attack. They have in some instances 

 been met with in such numbers, in association with a formidable 

 grub attack, as to arrest attention and to induce inquiry into their 

 character. 



For an interesting mention of a secondary parasitic attack — the 

 larva of the Tiphia, in its turn and while within its cocoon, 

 is destroyed by a beetle known as Rhipiphorus (Emmenadia) 

 pectinqtus Fabr., var. ventralis — see Riley, he. tit., p. 125. 



From a paper recently read by Mr. Otto Lugger, before the 

 Baltimore Naturalists' Field Club, it appears that the Rhiphophora 

 parasite above mentioned, which destroys the Tiphia parasite, has 

 a parasite which also destroys it. Mr. Lugger had found within 

 the Tiphia cocoons small hymenopterous parasites — the species 



