October, '14] WOLCOTT: ECOLOGY OF TIPHIA 383 



from the workers in Porto Rico — "Sir. Thomas H. Jones and 

 Mr. E. G. Smyth. 



The Uterature dealing with other than the taxonomic features of 

 Tiphia inornata is very meager. Dr. C. V, Riley in his Sixth Missouri 

 Report (pp. 123-126) is the first to record anything of its parasitic 

 habits, life history, abundance and parasitism by RhipipJiorus pectinatus 

 Fabr. He also quotes the original description of the adult by Say and 

 adds other descriptive notes, besides figuring the adult, larva and co- 

 coon. Prof. S. A. Forbes in the Twenty-fourth Illinois Report (pp. 

 157-160) gives much interesting and definite information regarding 

 the life history and habits, and the colored figure (Plate x) of the larva, 

 cocoon and adult is very good. jMr. J. J. Davis in Farmers' Bui. 543 

 on "Common White Grubs" (pp. 15-16) figures the cocoon and gives 

 some descriptive and life history notes. ]My attempt in this paper is 

 to add to the life history data and descriptive notes given by others, 

 but the discussion on the ecological factors is entirely original and has 

 not been touched upon by previous writers. 



Life History 



The adult Tiphia is entirely black with many grayish hairs on the 

 head, thorax and abdomen, and is easily distinguished from all other 

 wasps by the color and the constriction between the first and second 

 abdominal segments. The males are smaller and more slender than 

 the females. 



The female Tiphia is quite often observed on cement walks and on 

 the ground, and indeed she spends the major portion of her time in or 

 on the ground. She has at quick nervous walk, and her movements 

 give one the impression that her eager search is without definite plan. 

 Seldom is flight attempted, although the wings are used to help in 

 short jumps or quick changes of direction. Earthworm holes and all 

 sorts of cracks and Tioles are explored and often the wasp disappears 

 in a hole in the earth that proves attractive. The females have slight 

 difficulty in working their way through black heavy clay soil in good 

 tilth and seem to be successful in finding grubs even in a field where 

 they are not abundant. The grub is stung by the female wasp ujitil 

 it ceases to resist her attempts to deposit an egg on it, but the effect 

 of the sting is only temporary. Indeed, the grub is often so active in 

 burrowing through the soil that the egg, or even the young maggot, 

 may be rubbed off. Grubs are often found with a brownish lesion 

 showing the point of attachment of a maggot that has been rubbed 

 off. The egg may be deposited on either the dorsal or ventral surface 

 of the thorax of a one-third to fully grown grub. In one instance 

 where the egg was deposited on the dorsal surface of the abdomen, 



