( i-^ ) 



The experiments I refer to are simply this : if a sound 

 cocoon be taken, and with say the point of a penknife, an 

 attempt be made to remove such a lid, a fracture starts at the 

 spot where the penknife is applied, and a lid at once breaks 

 off. This lid is very similar to the one the moth makes, but 

 is less symmetrical, and may be considerably larger or smaller 

 than that is, and always starts at the point where pressure is 

 applied by the sharp implement. It is therefore similar to the 

 lid the moth makes, but not the same lid, and shows that 

 such a lid occurs wherever the forces applied determine, and 

 not along a specially-prepared line. The experiment is, indeed, 

 even more conclusive than this. It is not always easy to say 

 of a sound cocoon, which end is which, and if the wrong end 

 be attacked, a lid is removed just as correctly as at the right 

 one. It is here that the beak or ' cocoon-opener ' is useful 

 as determining that the fracture shall be at the right end, 

 making the lid split off here, under much less pressure than 

 would be efficient without it, and leaving no chance for fracture 

 to occur at the wrong end where pressure is equally distributed. 

 The Systro2nis breaks off a similar lid, no doubt by similar 

 end-to-end pressure to that exerted by the moth, Dijytera 

 having highly developed the habit of inflating themselves with 

 air, at emergence from the pupa. This pupa also has a beak 

 very like that of the Limacodid, but even stronger and 

 sharper. I have put in the box a Bombyliid pupa-case from 

 West Africa. It is very like that of some British forms. The 

 head-armature is not a ' cocoon-opener,' but an excavating or 

 navvying machine, for use in burrowing a way out of loose 

 soil, such as that in which solitary bees' nests are found. The 

 pupa of an African species of practically the same habits as this 

 South American one is described and figured in Prof. "West- 

 wood's monograph of the genus Systrojms in our Transactions 

 for 1876." 



jNIr. J. E. Collin, in further illustration of Dr. Chapman's 

 remarks, exhibited specimens of : (a) Systropus, sp. 1 from 

 Buenos Ayres, parasitic on a Bombycid Lepidopteron {Lima- 

 codes 1). This he said was possibly the same as Dr. Chapman 

 would have I'eared from his cocoons. The species was 

 appai-ently undescribed, but most allied to *S'. hrasiliensis, Meg. 



