ODYNERUS. 199 



The labium rather short, broad, and deeply notched at the 

 apex, the margins of the notch fringed with pubescence ; the 

 paraglossae nearly as long as the labium ; the labial palpi 4-jointed, 

 the basal joint as long as the three following, the apical one 

 minute. The maxillary palpi 6-jointed, the basal joint stout, 

 the following joints each becoming more slender to the apical 

 joint. Antennae simple, terminated by a hook, or with the apical 

 joints spiral in the males. 



This genus of Wasps is spread over all parts of the world. In 

 this country we have, as I believe, only twelve known species ; 

 their discrimination is extremely difficult, the colouring being 

 very inconstant, at least in two of the most abundant species ; 

 these are united in one species by Saussure in his monograph of 

 the Solitary Wasps : the reasons which have induced me to differ 

 from such an authority are, the fact of my having bred the insects, 

 and never having found what Saussure considers varieties, mixed, 

 and at the same time having found constant characters to sepa- 

 rate them. The species are here divided into sections in accord- 

 ance with the divisions made by Wesmael in his monograph of 

 the Odyneri of Belgium. 



Some of the species burrow in wood ; Odynerus trifasciatus 

 selects partly decayed rails, posts, or fencing. I have bred the 

 sexes, and have found scarcely any appreciable tendency to vary 

 in this species. 



Odynerus quadratus constructs its cells in old posts, &c., but 

 frequently, if not always, prefers some ready-made tunnel or hole 

 suitable to its oeconomy ; it is recorded by Mr. Ingpen to have 

 constructed its cells in the foldings of a piece of paper that had 

 fallen behind some books. I have found it making use of the 

 tubes of reeds used in thatching an outhouse in a farm-yard ; but 

 the most curious adaptation I have heard of, is its lining the 

 bores of a double-barreled pistol which hung on a post in an 

 arbour of a garden. It is stated to have been observed to store 

 up Diptera; but I have always found it to select the small 

 green larvae of Lepidoptera, probably of a species of Crambus. 



From a number of cells which I discovered in a hard sand- 

 bank, provisioned with small green caterpillars, I reared several 

 specimens of 0. Antilope; the contents of each cell were placed 

 in a separate pill-box; and from two, I not only obtained a 

 male Odynerus, but also a specimen of Hedychrum auratum. 



Odynerus spinipes is commonly subject to the parasitic attacks 

 of Chrysis bidentata, and I have occasionally observed Hedy- 

 chrum auratum entering its burrows. This wasp constructs the 



