34 BULLETIN 891, U. S. DEPARTMENT OE AGRICULTURE. 



about three-fourths of an inch from head to tip and with a wing 

 expanse of about an inch and a fourth. It is subject to considerable 

 variation, however, in size. The main color is black; the wings are 

 dusky with a purplish luster ; the first two segments of the abdomen 

 are similar, but the remaining abdominal segments are reddish 

 brown, the third segment being marked above with two conspicuous 

 transverse yellow spots. The female has comparatively short an- 

 tennae, and those of the male are nearly twice as long. 



In large collections which have been made and in observations 

 the male greatly predominates, females being decidedly rare. The 

 males are also more slender and smaller than the other sex and are 

 provided with strong clasping organs, which perhaps have the power 

 of puncturing the skin. The female is undoubtedly a poisonous 

 stinging form. The cocoon of this species is shown in figure 6, C. 



Our first report of this natural enemy of Cotinis nitkla was re- 

 ceived from Mr. F. W. Barclay, Haver ford, Pa., who wrote October 

 12, 1903, and sent numerous specimens of nearly grown larvae as well 

 as cocoons, showing dead beetles, and cocoons of this digger wasp. 

 He stated that the grubs at that time were becoming scarce. He 

 had observed two of these wasps enter holes made by the grubs and 

 remain there for a few minutes. It was the general opinion of the 

 men working on the grounds of the golf links at Haverford, where 

 the grubs were most injurious, that the wasps sting and kill the 

 grubs. If the grubs were dug up after the wasp had entered the 

 holes, the wasp would be found attached to them. He also stated 

 that the wasp killed the grubs, attacking them on the golf greens 

 in the morning. 



TVe also have record of this species occurring as a parasite of the 

 green June beetle at Harrisburg, Pa., made by the late H. O. Marsh, 

 Bureau of Entomology, about the middle of August, 1906. Numer- 

 ous individuals were observed flying over soil known to be infested 

 by the host larva and the wasps were observed to crawl into the bur- 

 rows made by the host. 



June 6, 1908, Mr. W. A. Kapner, Charlottesville, Va., wrote that 

 he had seen a wasp of this species collected September 21, 1907, 

 -carrying a larva of the beetle when taken. Swarms of the wasps 

 were flying in the autumn of 1907. In a later letter, June 12, our cor- 

 respondent stated that the wasp was seen dragging the host larva. 

 No doubt the females of this species are quite capable of doing this 

 work, although it would seem to be unusual for the group to have 

 this habit. It is remarkable in any case, since the wasp is so light 

 as to be seemingly incapable of flying with so large an object as this 

 grub, unless the latter is of small growth, more particularly because 

 the grub is usually full of humus and moisture, making it quite heavy 

 for its bulk. 



