Polysphincta.] BRITISH ICHNEUMONS. 127 



5. carbonata, Grav. 



Cryptus carhonator, Gr. Vergl. Uebers. z. Sjst. 1807, p. 264. Pimpla carbon- 

 ator, Gr. Nova Acta Acad. 1818, p. 290. PolyspJiincta carhonator, Gr. I.E. iii. 

 123; Holmgr. Sv. Ak. Handl. 1854, p. 90; lib. cit. 1860, n. 10, p. 31 ; Tasch. 

 Zeits. Ges. Nat. 1863, p. 272 ; Thorns. O.E. xii. 1251, <? ?; cf. Ratz. Ichn. d. 

 Forst. iii. 110 ct Brisch. Schr. Nat. Ges. Danz. 1880, p. 114. 



A shining and entirely black species, with the abdomen somewhat dull. 

 Head distinctly constricted behind the eyes ; palpi pale stramineous and 

 clvpeus rufescent. Antennae simple, filiform, longer than half the body 

 and nigrescent. Thorax gibbulous, immaculate or with a stramineous 

 radical callosity ; mesonotum nitidulous and not pubescent nor densely 

 punctate; metathoracic areola not very distinct. Scutellum entirely black. 

 Abdomen somewhat con\'ex, as long as the head and thorax and as broad 

 as or a little broader than the latter, of 9 gradually constricted basally 

 from the fourth segment, of ^ with the second to the fifth parallel-sided; 

 basal segment smooth and hardly subcanaliculate centrally ; segments two 

 to five transverse, very closely punctate and densely pubescent, with obso- 

 lete tubercles and impressions ; terebra one-sixth or one-eighth of the 

 abdomen with the valvulae black, stout and pilose ; spicula castaneous. 

 Legs somewhat stout and fulvous, with the apices of the femora and often 

 the (^ coxae infuscate ; anterior trochanters white, their coxae basally 

 black in 9 and internally white in ^ ; hind legs with apices of the tarsi 

 and of the tibiae, as w ell as a band before the white base of the latter, 

 infuscate and the J trochanters white ; apical hind tarsal joint as long as 

 the third. Wings normal, slightly clouded ; stigma and radius piceo- 

 stramineous, tegulae and radix either concolorous or whitish ; radial cell 

 lanceolate ; nervellus distinct, antefurcal and intercepting a little below 

 the centre ; cubital nervure of the lower wing not basally wanting. 

 Length, 4 — 6 mm. 



The (^ is a much more slender insect than the 9 ; both sexes var}' in 

 the extent of infuscesence of the coxae, of which (unlike P. tiiberosa) the 

 hind ones are not darker than the anterior, and of the 9 hind tibiae. It is 

 very like P. tuberoso but the head is less narrowed posteriorly, the areola 

 subobsolete, the abdomen distinctly explanate centrally and fully four 

 times as long as the terebra, which has more incrassate valvulae ; the 

 legs, though somewhat variably, are differently coloured and their femora 

 are stouter. P>om P. rufipcs, Grav., it may be known by the distinctly 

 nigrescent apices of the hind femora, shorter terebra and much less deter- 

 minately bicarinate basal segment. 



Blackwall tells us something of the economy of this species (Brit. 

 Assoc. Report, 1842, p. 68); he says that immature spiders of the species 

 Lyniphia pusilla, Sund. and Leptiphantts minit/us, Bl., "are frequently 

 infested by the larva of a small ichneumon, which feeds upon their juices 

 and ultimatt-ly occasions their death. This parasite is alwavs attached to 

 the upper part of the abdomen, near its union with the cephalothorax, 

 generally in a transverse but occasionally in a longitudinal position, and, 

 though it proves a source of constant irritation, is secured by its position 

 from every attempt of the spider to displace it. Being apodous, it appears 

 to retain its hold upon its victim solely by the instrumentality of the mouth 

 and of a viscid secretion emitted from its caudal extremity. More than 

 one larva is never seen on the same spider, which, indeed, could not supply 

 sufficient nourishment for two." Then follows a rough description of a 



