INTRODUCTORY PAPERS ON ICSNEUMONlDiE. tS 



different forms, as described b}- Wesmael in his 'Teutamen' 

 (p. 180). A sign is placed before each form, and these again will 

 be placed in parentheses before the insect to indicate the structure 

 of the coxae of each female. The genus Diadromus, Wesm., was 

 distinguished from Phceogenes by having the apex of the clypeus 

 abruptly depressed. Wesmael afterwards thought these two 

 genera might be united ; and as Mr. Marshall has merged them 

 in his catalogue we shall do the same. Phceogenes collaris was 

 included b.y Gravenhorst in the genus Ischnus, it having a very 

 prominent scutellum ; but Wesmael thought the petiole was too 

 long and slender for it to remain there, so he moved it to 

 Diadromus. 



(1.) The process beneath the hinder coxse in the form of an 



abrupt tooth. 

 (2.) The process in the form of an oblique keel, with the apex 

 produced into a longer or shorter (sometimes sub- 

 obsolete) tooth. 

 (x.) Keel of coxse straight or somewhat sinuous, 

 (xx.) Keel of coxse interrupted. 

 (3.) Process in the form of a small crest or oblique line. 

 (4.) Hind coxse without any process. 



Section 1.— Thorax and abdomen black ; antennae of female generally 



white-ringed. 



A. Femora and tibiae red (male and female). 



5. (2. X.) stimulator, 3J — 4 lines. 



B. Legs red ; hind tibiae and tarsi dark ; the former pale-ringed in the 



middle, the latter pale at the base of joints (male and female). 



6. (2. X.) calojnis, 2i — 3 lines (I, a). 



C. Legs almost entirely black (females). 



a. Antennae white-ringed. - 12. (4.) cephalutes, 3^ — 4i lines (a). 



b. Antennae red. (4.) similis, 2 J lines. 



Section 2. — Scutellum pale marked (sometimes black) ; abdomen black. 



Femora, front and intermediate tibiae, red (male). 



19. candidatus, 'd\ lines (s). 



Section 3. — Scutellum pale (white or whitish, A and C ; red, Bj; abdo- 

 men red and black. 



A. Abdomen red, base more or less black or fuscous; antennae white- 

 ringed (females). 

 a. Legs red ; front co.\ae whitish ; spine on hind coxte long. 



4. (1.) scutellaris, 2^ — 3 lines (s). 



