upon lepidopterous larva, dec. 305 



from those observed last year, which after detachment 

 lost the glistening appearance. The Dicranura larva 

 had not been allowed to construct a cocoon, but No. '3) 

 was contained in one, which was opened at this date, 

 when it was seen that the single parasite was still 

 small, although it was growing. 



On Sept. 8th, when the former larva was beginning 

 to spin, having ceased to feed a day or two earlier, I saw 

 in the box a freshly formed and still undarkened pupa of 

 some internal dipterous parasite. Hence the D. vinula 

 had been simultaneously attacked by internal and 

 external parasites of very different kinds. On Oct. 4th 

 the box was opened, and it was found that the dipterous 

 imago had emerged from the pupa many days before, 

 and was dead. The species was ascertained to be 

 Tachina quadripustulata . 



On Sept. 11th the larva had constructed a large 

 scaffolding of white silk over the remains of the 

 Dicranura and the dipterous pupa. The larva No. (3) had 

 now become very large, although not quite so large as 

 the other ; it had just begun to spin, having ceased to 

 feed at about this date. From the previous observation 

 of this larva it was seen that all the increase in size 

 which follows an unusual supply of nourishment takes 

 place after detachment, and that the larvae are of nearly 

 uniform size when they are detached. The length of 

 the larva at this date was 22*5 mm., when rather 

 stretched and very nearly straight. 



On Sept. 16th the larva was rather smaller, having 

 become slightly shrunken during the process of spinning 

 a scaffolding. At this date it was drawn from two 

 points of view, and it is seen in Plate X., fig. 14 

 (ventral view), and fig. 15 (lateral view), both figures 

 being of the natural size. The silk spun by both the 

 larvae was white at first, but subsequently became dark. 

 No. (3) did not construct a cocoon, but expended its silk 

 in making a large scaffolding in the chip-box, but the 

 central depression in which the larva now lies has the 

 form of a furrow with well-defined sides, and probably 

 represents the beginning of a cocoon. Larva No. (2), as 

 it wandered over the chip-box spinning a scaffolding, 

 came upon the hard cocoon which had been spun by the 

 J >. vinula, and entered through the hole by which the 

 latter had been removed. In the smaller cavity it 



