moo.] 119 



bordered before the sqnamulso, which arc bright flavous, central line dividing the 

 mesopleurse narrow and somewhat shallow ; scutellum and post-scutellum always 

 fully developed, flat, black, distinctly punctured and somewhat shining ; metathorax 

 tumidulous, arese obsolete, transverse ridge strong, though not produced laterally, 

 continued along the lateral margin to sides of the mesothorax, just before this ridge 

 is a row of longitudinal striations,* spiracles not very large, oval. 



Abdomen broad-ovate (scarcely more than ovate in the macroptcrous form), 

 red ; first segment black, infuscate at the apex ; at least seven segments exserted ; 

 very thickly and finely punctured throughout, each puncture is furnished with a 

 short whitish hair (not, I think, thicker towards the apex ; cf. Curtis), which lends 

 the surface a very smooth and somewhat dull appearance ; only the punctures on the 

 first segment are confluent, those at the apex of the second segment are larger ; in 

 Mr. Donisthorpe's specimen the 2nd segment on either side the dorsum, and the 3rd 

 on the left side only, is an obvious pore at the apical third, but I have detected this 

 character in no other specimen examined, and it is undoubtedly accidental ; dis- 

 tinctly petiolated (Ratzeburg says almost sessile, and Westwood sessile) ; the petiole 

 bears large spiracles and is generally broadly explanate at the apex, before which it 

 is indistinctly aciculate ; 2nd and 4th segments with prominent lateral spiracles, 

 decreasing in size and distance from apical margin ; apex generally infuscate ; under- 

 side sometimes with a central fold on the 2nd and 3rd segments ; the length of the 

 terehra would appear to vary : Ratzeburg says distinctly exserted, Curtis scarcely 

 exserted, but all I have examined agree with Westwood in not reaching the apex 

 of the abdomen. 



Legs robust, especially the posterior pair, and by no means short ; red, coxse 

 and trochanters black, the latter fulvous or flavous at their apices ; apex of posterior 

 tibise and whole of tarsi fuscous ; tarsi quinquearticulate, first joint half their entire 

 length, claws very small and simple, pulvilli minute. The Wings in the macropte- 

 rous form are 5^ mm. each in length (in the brachypterous only 4 mm.,t with the 

 nervures comparatively stronger), quite transparent, the nervures fuscous, becoming 

 fulvous towards tlie base ; stigma darker ; radices flavous ; areola wanting ; exterior 

 discoidal recurrent nervure somewhat pellucid in its centre. Length, 6 mm. 



Curtis (Brit. Ent., pi. 198) has beautifully figured the brachyp- 

 terous form, though the antennae are very slightly too long ; with 

 details of the head, labrum, mandibles, maxillae, mentum, and the 

 anterior leg. Andre (Spp. Hymen. d'Europe, pi. xxxiv, fig. 6) some- 

 what indifferently sketches the macropterous form. 



The life-history of Sphegophaga is most interesting, if only as a 

 striking example of seasonal dimorphism. The eggs appear to be 



* Tljese were also noticed by Ratzeburg, but they are, I fancy, present in at most the bra- 

 chypterous form only. I think it probable Ratzeburg's description whs taken from a slightly 

 immature specimen ; such are not uncommon when taken from the nest. He says the meta- 

 thoi-ax is wrinkled with feebly demarkated arese, and makes no mention of the strong transverse 

 ridge. Curtis, on the contrary, says it is deeply sculptured. 



t Bignell (Ent. Mo Mag., xxvi, 191) gives the length of the body and the expansion of the 

 wings respectively as e mm and 9 mm in the brachypterous, 7 mm. and 13 mm. in the macrop- 

 terous form. I have not, however, noticed that the latter exceeds the former in the average 

 length of the body. Curtis gives the former at fij and 9 mm. 



