EXTERNAL PARASITES OF SPIDERS. 175 



four in the centre. The object of these was to suspend itself by 

 the web while feeding on the last remains of its victim, and 

 holding on after it was consumed ; when the whole of the spider's 

 body had been extracted, the legs and empty skin were allowed to 

 fall down. The larva then commenced to make itself a cocoon, 

 which was finished by the third day ; it was during this time the 

 tubercles had to play such a prominent part, having to perform 

 the work of the claspers of an ordinary caterpillar ; when a 

 tentacle attached to the silken cord had to be removed, it was 

 done by withdrawing the booklets into the tentacle, when it at 

 once became disengaged and ready to make another 'attachment.' 

 From one spiracular line to the other were rows of black dots, 

 two on the 2nd segment and one on the remainder ; the centre of 

 each was occupied by a short hair. The anal segment often had 

 a very important part to perform, by being brought round to the 

 assistance of the mouth ; I first observed this while it was feeding, 

 to disengage some internal portion of the spider from its jaws; 

 afterwards it was frequently used to attach the silk to some part 

 of the cocoon when the blunt round head of the larva appeared 

 not to be able to attach the silk to its satisfaction. When full 

 fed the larva was about three -eighths of an inch in length. 

 I have no hesitation in saying that this larva had fourteen 

 segments (counting the head as one). Cocoon shuttle-shaped, 

 whitish, and thin ; the movements of the larva and pupa were 

 perceptible through the thin cocoon. The perfect insect appeared 

 on the 12th June." 



Mr. Matthews' account of the larva changing colour before 

 and after a meal is confirmatory of what Brischke says ; and Mr. 

 Bignell's express statement that the larva lias fourteen segments 

 is confirmatory of Laboulbene's descrijition. Mr. J. B. Bridgman 

 has seen and named both sjjecies, and, referring to P. tuherosa, 

 writes, " I have the same species, given to me by Mr. F. Norgate, 

 with the cocoon and spider-skin exactly like Mr. Bignell's" 



The woodcut represents Polysphincta tuherosa, Grav., female, 

 with its thin white cocoon on the right, to the extremity of which 

 is attached a curious small black tassel of excrement. The larva 

 (from Mr. Bignell's drawing) is represented below, with an 

 enlarged figure of the head. The thick ochreous cocoon on the 

 left is that of Mr. Matthews' species {Polysphincta pallipcs, 

 Holmgr. ?). 



jNIaldon, Essex, July, 18y2. 



