MONOGRAPHIA CHALCIDUM. 13 



canaliculatum : abdomen cylindricum aut gibboso-compressum. 

 petiolatum, segmentis 7 : aculeus subexsertus : coxae magnae : 

 femora subclavata : tibiae apice spinis duabus armatae : tarsi 

 5-articulati, articulo prime longiore, sequentibus longitudine 

 decreseentibus : ungues arcuatae. 



In external appearance, this family seems to have many 

 affinities with Smiera, Chalcis, and Haltichella, to which, with 

 Dirhinus, Dolman, and Chirocera, Latreille, I propose restrict- 

 ing the term Chalcididag. They and the Eurytomidae differ from 

 the rest of the Chalcides in their large quadrate proscutellum 

 or collar, which is noticed by Dalman as the distinguishing 

 character of Eurytoma. The trophi, however, of these two 

 families are very different, and the Eurytomidae may be easily 

 known by their smaller coxae, more slender thighs, and less 

 arcuate tibiae. Dalman remarks of Spalangia, which he places 

 next to Eurytoma, that it resembles it in habit; but that the 

 form of the head is totally different. Cerocephala, Westwood, 

 may possibly be an intermediate genus, between which and 

 Spalangia, the only apparent external difference consists in 

 the horned head of the former : perhaps the stigmal branch of 

 the anterior wing varies slightly. Another genus, as yet 

 undescribed, one species of which is common on box-trees, in 

 the spring, is closely allied to Eurytoma longula in habit, 

 though its biarticulate palpi bring it near to Spalangia. The 

 colour of all the Eurytomidae I have seen is black, sometimes 

 variegated with yellow or red, without any metallic hue, in 

 which they resemble the Chalcididse. They are usually found 

 in marshy places, or in the vicinity of ditches. The species of 

 Decatoma, however, are found in woods beneath oak-trees, &c. 

 I have been informed by Mr. Davis, that he has obtained an 

 individual of the latter genus from an oak-gall. This fact 

 shews it to be similar to the Torymidas in economy, one 

 genus of which, Megastigmus, it also resembles in structure. 



Characteres Generum. 



i elongatum, gracile : y^m. an- 

 \ tennae apice rotundatae . . 1. Isosoma. 

 cylindricum: Corpus ) 



j breve, crassum : fern, antennae 



,, , , ( apice acuminatse .... 2. Systole. 



Abdoiiieiu ; . .„ 



(( mas, setacea; verticillato 

 comyres^ium. Jnlcnn J F^°^*= f'"^' '^'^^"t«-' • • 3- Eurytoma. 

 / mas, etfem. clavata; . . 4. Decatoma. 



