EURTTOMIDi!. 23 



Dr. Walsh describes the five following American species of Deca- 

 toma, four of which inhabit oak-galls and one willow-galls also : — 

 varians, nigriceps, nubilistigma, hyalipennis, simplicistigma. They 

 have the same variation in the " colorational pattern " that is 

 exhibited by the British species. D. pigra, Motsch., a Ceylonese 

 species, is probably not a Decatoma. 



It seems that there is no definite line between Eurytoma and 

 Isosoma, but it is advisable to retain the latter genus, I. verticillata 

 being its type, and E. plumata the type of Eurytoma. The genus 

 Tetramesa may be united to Eurytoma. 



In passing away from the Eurytomida?, I wish to recommend them 

 to the attention of the public. They are especially interesting, as 

 being partly exceptions to the rule that all the Chalcidiae are beneficial 

 insects ; and much investigation is required to ascertain whether 

 some of them are wholly herbivorous and the rest wholly carnivorous, 

 or whether the species have a capacity for either means of sustenance. 

 There is a gradual transition from them to the Torymidae, by means 

 of the genera Decatoma and Megastigmus. 



Genus EURYTOMA. 



E. exempta. Mas. — Nigra, gracilis, E. gracili longior, subtilis- 

 sime punctata ; antennae graciles, verticillato-pilosae, thorace paullo 

 longiores, articulis petiolatis subdilatatis ; petiolus longus ; abdo- 

 men brevi-lanceolatum, valde convexum, vix compressum, thoracis 

 dimidio vix longius ; pedes nigri, genubus tarsisque fulvis ; alae 

 diaphanae, fulvo venosae. 



Male. — Black, slender. Head and thorax finely punctured. 

 Antennas slender, verticillate-pilose a little longer than the thorax ; 

 joints slightly dilated on one side, with rather long petioles. Petiole 

 long. Abdomen very convex, short-lanceolate, hardly more than half 

 the length of the thorax, hardly compressed. Knees and tarsi tawny. 

 Wings pellucid ; veins dull tawny ; ulna a little more than half the 

 length of the humerus ; radius very short ; cubitus a little more than 

 half the length of the ulna. Length of the body 1£ line. 



The body is longer than that of E. gracilis, which it most 

 resembles. 



England. 



E. intermissa. Fcem. — Nigra, gracillima, subtiliter punctata; 

 antennae graciles, subclavatae, thorace multo breviores ; petiolus 

 brevis ; abdomen lanceolatum, glabrum, nitens, thorace paullo lon- 

 gius ; pedes nigri, genubus tarsisque albidis ; alae diaphanae, albido 



