184 [August, 



of tlie abdomen fixed aud steady, so that the thrust may be direct and 

 true. 



In pusliing a slender object, like a needle, into any resisting mass, 

 if it be held at a distance from the object, it is dilHcult to advance it 

 so steadily that it does not bend and l)reak ; or if, unlike a needle, it 

 is flexible enough not to break, it will dou])le up and go no further. 

 In either case the operation will succeed if the needle be held steadily, 

 fairly close to the object to be pierced. In tlie case of the Chrysis, the 

 short grip and the steadiness of the fulcrum is secui-ed by the terminal 

 teeth engaging the rough surface of the cocoon. The actual fulcrum, 

 however, must be taken by the insect in some other way, either by its 

 legs or by pressure against the wall of the burrow in which the 

 cocoon is. 



Chrysis ujnita has a toothed margin, yet in the only cases in 

 which I noted its ovipositing habits, it did so in the open cell. This 

 would tell against my theory of the use of the teeth, but ignita is an 

 abundant species, attacking a number of different hosts, and probably 

 commands with this object different procedures in different cases, 

 procedures that with other species of the genus are each confined to 

 one species. 



The dentate margin is not, however, a sexual but a specific 

 character. This seemed to me at first a difiiculty, but I think a 

 secondary sexual character is often transferred to the opposite sex, and 

 if not injurious when so transferred, may easily become a specific 

 character. Darwin refers to a good many cases of secondary sexual 

 characters being transferred to the opposite sex. There are really 

 many such cases, which we do not usually recognise : In Balaninus, 

 for instance ; the female requires a long rostrum to reach the proper 

 point at which to deposit her egg. The shorter, but still very long, 

 rostrum of the male is, so far as I know, of no special use. A curious 

 instance of what seems to be a transfer to the male of what is almost 

 a primary sexual character, occurs in some Sphinges. The cephalic 

 margin of the 8th abdominal st^rnite is prolonged in a way that can 

 hardly be anything but an echo of the female structure of this plate. 



M. du Buysson (Andre's Hymenopteres, Vol. VI, p. 32) strongly 

 asserts that Chrysis only eats the larva of Odynervs and not the pro- 

 visions. He obviously never saw my paper (Ent. Mo. Mag., Vol. VI, 

 p. 154), nor can he have made any observations on Chrysis neglecta 

 with reasonable care, or he would not say it only eats the Odynerus 



