ivhose Larva is parasitic on Spiders. 3 



the abdomen. The ovipositor was hairy, very dark brown, 

 and measured ^th of an inch in length. 



On the 20th of July 1 838, 1 obtained a young female Epe'ira 

 antriada, to whose abdomen a full-grown larva of this Ichneu- 

 mon was attached, and placed it in a phial. On the 23rd the 

 larva became restless and destroyed the spider, after having 

 reduced it to a mere corrugated skin ; then quitting it, and 

 taking its station on the extremity of the cork w-hich stopped 

 the phial, it commenced spinning its cocoon, and completed 

 it on the 24th. 



Out of this cocoon, which exactly resembled the one de- 

 scribed above in figure and colour, though it was somewhat 

 less, a male Ichneumon issued on the 16th of August. 



This insect w 7 as without ovipositor, and was smaller than 

 the female bred from the larva found on the female Epe'ira 

 antriada captured in April 1838; its antennae also had each 

 twenty-tw 7 o joints only ; but these differences may be regarded 

 as sexual peculiarities merely ; the close resemblance of the 

 two insects in other particulars, and the exact correspondence 

 in the oeconomy of their larvae, leave no doubt about their 

 specific identity. 



On the 26th of October 1841, I caught an adult female 

 Linyphia minuta with a parasitic larva, which had completed 

 its moulting, fixed upon its abdomen, and enclosing it in a 

 phial I fed it with flies. The larva increased in growth till 

 the 1st of February 1842, when it destroyed the spider, which 

 was much reduced in size, and having quitted it, attached 

 itself to the under side of a slight horizontal sheet of web 

 previously constructed in the phial by the spider. In this 

 situation it remained till the evening of the same day, when 

 it commenced spinning its cocoon, and on the evening of the 

 day following had completed it. This cocoon was composed 

 of brown silk of a compact texture, and was of an oblong 

 quadrilateral form tapering to its extremities, one of which 

 was more pointed than the other. 



As this insect did not go through its final metamorphosis, 

 I am unable to decide whether it differed specifically from 

 those already described or not ; but it is very probable that 

 it did not, as the dissimilarity in the colour of the silk com- 

 posing its cocoon may be reasonably ascribed to the quality 

 of the food derived from a different species of spider, for it is 

 a well-know r n fact that animal secretions are frequently modi- 

 fied in colour by changes of diet. As for the circumstance 

 of the cocoon having been connected with the web of the 

 spider which supplied the larva with sustenance, it may be 

 considered as accidental ; at all events, the spiders in the two 

 former cases detailed in this paper did not construct webs, 



B2 



