Polysphincla.] BRITISH ICHNEUMONS. 125 



labrum rufescent, the antennae consisted of about 25 joints, the thorax 

 was very finely punctate with fine pubescence, the apices of some of the 

 intermediate tarsal joints were infuscate, the apices of the hind femora 

 nigrescent, the abdomen was punctate and pubescent ; and the basal 

 segment of the beautiful figure (pi. xvii, no. 11, fig. 11) is represented as 

 distinctly bicarinate throughout and apically tuberculate in the centre. 

 So minute is the description that the interalar hooks of the hind wings 

 are said to be arcuate, simple and five or six in number, of various sizes 

 (fig. 10). 



In June, 1856, Laboulbene found in the Park de Villegenis three satiny 

 grey and slightlv shining larvae in a dry and curled leaf on an oak tree. 

 Thev were slightlv moving in the centre of a white bundle of spiders' web, 

 on which was a dead spider, Cliihiona holosericiti, De(r., which is common 

 in Britain. The larvae moved their heads horizontally and seemed 

 affixed by their legs, which are on the dorsal and not the ventral surface; 

 with these they walked slowly, holding their heads erect. One speci- 

 men was killed for examination and the other two bottled for observa- 

 tion. A fortnight later two females of Polysphincta multicoJora had emer- 

 ged and were already dead when discovered. They had emerged from a 

 silken, oblong, fine, whitish cocoon, spun by the larvae. 



The larva is elongate, a little curved and consists of fourteen segments, 

 including the anal tubercle ; the colour is whitish-grey, slightly shining 

 and satiny. The alimentary canal appears interiorly brown and, beneath 

 the tegumentary envelope, is a multitude of whitish granules, which are 

 immediately below the skin ; these have been very perfectly described by 

 M. Fabre in the larva of Sphcx flavipennis as a composition of uric salt, 

 serving as organs of excretion (Ann. Sci. nat., Zool. ser. 4, vi, p. 167) and 

 M. Barthelemy has further proved their uric nature in the Tachinid, 

 Scenometopia atropivora {lib. cit. vii. p. 1 15). The head of the larva is small, 

 curvilinear-triangular in shape, brown and furnished with two small and 

 biarticulate antennae ; its clypeus is subcircular and ciliated ; and there 

 are two mandibles, though the oral organs are very difficult to distinguish. 

 The thoracic segments are the largest and are dorsally and laterally 

 rounded. The abdominal segments are, perhaps, though at most incon- 

 spicuously laterally lobed ; the first to the seventh bear true retractile 

 pseudofeet, similar to those of Lepidoptcrous lars'ae, in the centre of the 

 back, each having, also like them, a circle of hooks which holds firmlv in 

 any position. The eighth and ninth segments are trapezoidal and form, 

 with the anal appendage, an inverted cone. There are nine pairs of 

 spiracles, the first being on the anterior margin of the metathorax ; the 

 second on the basal abdominal segment, i.e. the fourth of the larva ; the 

 third to ninth pairs are on the second to eighth abdominal segments. A 

 long tracheal tube traverses the length of the body and branches laterally 

 to each spiracle. These tracheae are white, silvery in the intestinal tube, 

 and the apical as well as those to its corresponding spiracles appears 

 black through the transparency of the larva's body under a microscope. 

 The ventral region in general is concave, smooth and apodous ; the sides 

 of the body are strongly rounded ; but the most important point of the 

 whole larva is the dorsal pseudofeet in the centre of the dorsal region. 

 Length, 7 mm. Laboulbene, almost certainly erroneously, concluded 

 that these lar\ae had subsisted upon the material of the spider's web and 

 not upon the spider itself. He gives no description of the pupa ; and 

 simply says that their cast skins present no features of interest. 



