APHIDIVOEOUS CEABRONID^. 1G3 



reduction of these insects, and to act as cliecks on the 

 development of Aphis Ufe. 



It would appear that Aphides form the nourishment 

 of the greater part of the PemphredonidfB, such as are 

 included in the genera Pemphredon, Cemonus, Dio- 

 dontus, Passala3cus, and Stigmus. Giraud states that 

 the genus Celia seems to confine itself to the storing 

 of Cocci for its young. 



The Crabronidffi do not tunnel in the hard ligneous 

 portions of the bramble stems, but choose the softer 

 pithy parts. They enter those twigs where the pith 

 has been exposed by fractures, or the cut of a knife. 



" Leurs premiers travaux sout masques par I'espece 

 de toit que forme la section en biseau,"* and what is of 

 greater importance, the mouth of the gallery is pro- 

 tected against the intrusion of rain, which, if allowed 

 to enter, would be most destructive to the inmates. 



I append the following short list of Aphidivorous 

 Crabronida3, with a few remarks on the species, chiefly 

 taken from the observations of the above authors. 



Craho Panzeri, on the authority of Shuckard, pro- 

 vides its larvse with living Aphides. 



Pemphredon lugubris, Fabr., was seen by Kennedy 

 to burrow in decayed wood and to throw out the saw- 

 dust, depositing Aphides.! Both Latreille and Shuc- 

 kard had before noticed its Aphidivorous habit. It 

 does not appear to be a pith borer ; at least it is not 

 noticed as such by Giraud. 



Pemphredon (Cemonus) unicolor, Panz., is common 

 about hedgerows. Giraud observes, under the head- 

 ing Cemonus unicolor, that he had already demon- 

 strated, in a Memoir published in 1863 at Vienna, J 

 that this insect excavates the stems of the rose and 

 briar, and " quelle approvisionne ses cellules de petits 

 Aphis apteres et a abdomen bitubercule." He says he is 

 certain of his facts, and that the insect is by no means 



* J. Giraud, 1. c, p. 446; Shuckard, 1. c, p. 174. 



t A. Kennedy, p. 17. 



X Giraud, ' Verhandl. dor Zool.-bot. Gesellscliaft.' 



